Method of inspecting quality of led structure. RU patent 2521119.
 Method to determine electroconductivity and thickness of semiconductor plates or nanometer semiconductor layers in structures "semiconductor layer - semiconductor substrate" / 2517200Invention relates to control and measurement equipment. The method to determine electroconductivity and thickness of a semiconductor layer includes radiation of a layer with electromagnetic radiation of microwave range, measurement of frequency dependence of coefficient of reflection of electromagnet radiation of microwave range, according to the solution, they use a unidimensional waveguide microwave photon crystal, where they create disturbance to periodicity in the form of a varied thickness of the central air layer. Previously they place the measured semiconductor layer inside the central layer at the specified distance from its border, additionally they measure frequency dependence of the coefficient of passage of electromagnetic radiation of microwave range, then they place the measured semiconductor layer inside the central layer at a new distance from its border or vary thickness of the central layer, they measure frequency dependences of the coefficient of reflection and passage of electromagnetic radiation of microwave range, interacting with a photon crystal, at new position of the investigated semiconductor structure or at new value of thickness of the central layer, they calculate, using a computer, values of thickness and electroconductivity, at which theoretical frequency dependences of coefficients of reflection and passage of electromagnetic radiation produced at two distances from the border of the central layer to the investigated semiconductor structure or at two values of thickness of the central layer, most close to measured in these positions from solving a system of equations. |
 Method to control defect structure of epitaxial silicon layers on dielectric substrates / 2515415In the method to control defect structure of epitaxial silicon layers on dielectric substrates, including preparation of the sample surface, exposure to radiation with wave length λ=380÷630 nm to a sample, rotating around the vertical axis and moving in the horizontal direction relative to the falling radiation, registration of amplitudes of the recorded signal, calculation of relative defect structure of the epitaxial layer Ndef and comparison of the calculated value Ndef with the available value Ndef (ref) of the comparison reference, the sample is exposed to pulses with duration of τ1=50÷100 mcs and porosity τ2=250÷500 mcs, the recorded signal is the amplitude Uout of the induced photo-EMF in the epitaxial layer of silicon, and relative defect structure of the epitaxial layer is calculated based on the ratio: U o u t / U o u t ( min ) = N d e f ( э т ) / N d e f , where Uout(min) - minimum of the recorded values Uout. |
 Method of increasing yield ratio when manufacturing high-density electronic modules / 2511007Invention relates to microelectronics and can be used to increase yield ratio when manufacturing high-density electronic modules. When manufacturing high-density electronic modules by forming built-in passive elements, directly assembling active elements (chips) and layered formation of interconnections before manufacturing and assembling the electronic elements, a modification of the circuit is produced, which is intended only for testing thereof, and multifunctional probing of operating capacity of each element is carried out using processing procedures after forming passive elements and assembling active elements and before forming interconnections. |
 Method of determining resistance of electronic components and units of radioelectronic equipment to ionising radiation / 2504862Method involves using three parametric Weilbull distributions or a confidence interval the inner boundaries (u - lower and v - upper) of which are obtained based on processing experimental exposure data of a sample with a size n, outer boundaries (U - lower and V - upper) are set from common physical presentations, the defining presentations of which are the level of absence of observed critical changes and slight (20-30%) exceeding of requirements for resistance of units to the effect of ionising radiation; including the experimentally obtained integral function of distribution of lower acceptable levels of resistance to different types of ionising radiation in the selected boundaries (U, V); determining the rate of change of probability of parametric or functional failures (intensity of variation of the parametric resource); plotting a family of curves of the distribution function F(U, x) of different types of ionising radiations (neutron fluence (Fn); gamma/X-ray radiation dose rate (Pγ-x-Ray); full absorbed dose (Dγ-x-Ray); heavy charged particle fluence Fion; linear energy loss value (LET) (for spacecraft-mounted equipment, etc) at fixed values ; determining from the plotted curves the radiation load level where the failure probability of the device is Fcrit, or the operability maintenance resource Rsokhr=1-Fcrit. |
 Method of measuring diffusion length of minority charge carriers in semiconductors and test structure for implementation thereof / 2501116Contact electrodes which are insulated from the base layer by a dielectric layer are made in the test structure which is made on a common base layer on the surface of p-n or n-p junctions of photodiodes. The radii of contact electrodes are greater than the radii of p-n or n-p junctions of photodiodes and have a common axis of symmetry. A contact is made on the surface of the base layer. The test structure is illuminated in the absorption spectral range of the base layer on the side of contact electrodes which are not transparent for infrared radiation. Photodiode photocurrents are measured and the ratios of photocurrents of two photodiodes in the test structure are determined. Theoretical calculation of photocurrents of different photodiodes of the test structure is performed and curves of the ratio of photocurrents of photodiodes versus the diffusion length of minority charge carriers are plotted. The measured photocurrent ratios are compared with theoretical values calculated from the curves and the diffusion length of minority charge carriers is determined. |
 Contacting device / 2498449Contacting device is made as a frame with a flexible printed circuit stretched on it and protrusion with external connector; at the flexible printed circuit there are oriented fixed patterns with reach-through windows for placement of controlled electronic components; at surface of the flexible printed circuit conductors with their peaks form lamellae with contact areas in compliance with topology of contact areas for the controlled components. At that total gap between the pattern window and electronic component should not exceed the distance between adjoining lamellae; between the base of contacting device and flexible printed circuit there is an elastic gasket made of material having properties of elastic strain; electronic components placed in the pattern windows at the other side have a thermal contact with heat sink which serves at the same time as a mechanical holdback; at the surface of heat sink and frame contacting with flexible printed circuit there is an applied electric insulating coating. |
 Method of diagnosing semiconductor epitaxial heterostructures / 2498277In the method of diagnosing semiconductor epitaxial heterostructures, which involves step-by-step scanning of a sample in Bragg reflection conditions, carried out by varying the angle of incidence of the X-ray beam, using single-crystal X-ray diffractormetry with a non-monochromatic, quasi-parallel X-ray beam and a position-sensitive detector, the X-ray tube and the detector are placed relative the angular position of the characteristic peak θ from one of the systems of crystallographic planes of the heterostructure at an angle θ1=θ±(0.5°-4°); based on the deviation of the position of the interference peak of deceleration radiation on the scale of the detector from the angle of incidence of the X-ray beam, the error of the position of the sample is determined; based on the obtained error, the tube is placed in a position Δθ by independent displacement, where the axis of symmetry between the tube and the detector is perpendicular to the chosen system of crystallographic planes; at that position of the tube, step-by-step scanning is carried out in a range of angles which characterise the selected system of crystallographic planes; through independent displacement, the tube is placed at an angle Δθ1=Δθ±(0.2°-1°), thereby bringing the maximum of the deceleration peak beyond the boundaries of the characteristic peak; step-by-step scanning of all layers of the heterostructure is performed, leaving unchanged the angular position of the characteristic peak from the system of crystallographic planes by moving the scale of the detector, and angular positions of the peaks of all layers of the heterostructure are determined. |
 Method of detecting quantum dots and apparatus for realising said method / 2493631In the method of detecting quantum dots located on a diagnosed sample, the sample is scanned in steps on XY coordinates using an electroconductive nano-sized needle with picosecond resolution and performing analysis of electrodynamic characteristics. Analysis is performed as follows: a semiconductor quantum dot is electrically exposed to a stimulating rectangular pulse; an analogue response signal is received and converted to a discrete signal; the information part of the response is picked up and identified with respect to a given class of dispersion of dynamic characteristics; coordinates XY are stored in memory and the topologies of the detected quantum dots with parameters included in given pre-start zones are displayed. |
 Method of measuring local electromagnetic fields on surface of heterostructures / 2491679Method involves measuring, in geometry based on signal reflection, a second harmonic from a sample surface irradiated with picosecond laser pulses with power required to generate a second optical harmonic but not higher than breakdown power. The polarisation direction of linearly polarised pumping radiation is gradually varied by turning a half-wave plate. While varying the polarisation direction of pumping radiation, an analyser which transmits second harmonic radiation is rotated in order to determine morphological features of components of the layer of semiconductor crystals. Scanning the layer of microcrystals while varying the distance from the focusing lens to the sample under strict focusing conditions enables to determine the quality of the heterostructure on the thickness. |
 Method to detect structural defects in silicon / 2486630Method includes radiation of an object in n-points with continuous probing IR-radiation L1 with wave length λ1≤5.0 mcm, registration of intensity In of radiation L1 that has passed through the object and mathematical processing of registration results. At the same time the object is additionally radiated with pulse IR-radiation L2, which crosses the radiation L1 with wave length λ2=1.0÷1.3 mcm, pulse duration Δτ2=0.8÷1.0 ms and pulse repetition rate ω2=0.6÷1.0 mcs, registration of intensity In is carried out during the period between pulses of radiation L2. Visualisation of structural defects distribution in the object volume is carried out according to the ratio In/Imax, where Imax - maximum of the recorded values In. |
 Method for determining silylation selectivity in photolithographic processes using chemical gas-phase modification of photoresist film near-surface layer / 2244363Proposed method meant for use in submicron lithography and in particular in production of elements of submicron-size structures on semiconductor and other substrates to test material during early stage of its manufacture for its silylation ability includes measurement of variation rates of refractive indices of exposed and unexposed photoresist films, respectively, in the course of their silylation by means of automatic ellipsometer and use of their measurement results to calculate selectivity from formula This method provides for determining selectivity of polymeric-film near-surface silylation directly in the course of gas-phase chemical modification and for doing so at any moment, that is to test source material for silylation ability. |
 Method for equalizing of reliability at rejection of semiconductor devices / 2247402The method consists in determination of lots with a reduced percentage of yield of satisfactory products after each check operation. The dominant type of reject of products of the given lot is revealed, the scope of additional rejection tests is determined, and total additional rejection tests are carried out. After the additional tests the lot is returned to the initial check operation. |
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Method for rejection of unreliable low-power transistors / 2247403 The method consists in passing of a series of collector direct current pulses through the device under test and measurement of the electric parameters for compliance with the specifications, it is featured by the fact that the amplitude of the pulse current is preset within 0.9 to 0.95 of the allowable value, pulse time - 1-2 seconds and up to 10 pulses. |
 Method for measuring electrophysical parameters of thin silicon dioxide films of gates / 2248067Proposed method includes evaluation of set of parameters of many MIS structures on entire wafer within its single trace, measurement of pre-breakdown current-voltage characteristic of MIS structure, breakdown voltage of gate insulator and charge injected in gate dielectric before its irreversible breakdown in single measurement process. Thus, electrophysical parameters of MIS structure are determined within singe measurement cycle. |
 Method for contactless detection of near-surface bend of semiconductor energy band / 2248068Proposed method that can be used for contactless evaluation of near-surface bend of semiconductor specimen energy bands including wafers covered with natural oxide or that applied by dielectric technique involves use of Kelvin probe to measure surface potentials in the dark and at least two times while illuminating semiconductor surface with light from inherent absorption region with known intensity ratio. Contact potential differences obtained in the dark and at different light intensity ratios are used to calculate near-surface bend of semiconductor energy bands by numeric solution of equation derived from constant value of near-surface semiconductor area. |
 Method and device for monitoring end-of-etching moment in high- frequency and microwave discharge plasma used in semiconductor device manufacturing technology / 2248645Proposed method used for monitoring moment of completion of plasma-chemical etching of micro- and nanoelectronic structure layers includes measurement and treatment of plasma optical emission modulated signal at characteristic wavelength of particle-reagent or particle-product of surface reaction whose intensity varies at end-of-etching moment for layer being removed within area of open windows in lithographic mark; for the purpose use is made of forced low-frequency amplitude modulation of high or microwave carrier frequency of plasma-shaping generator affording modulation of optical plasma emission followed by recording emissive intensity of plasma component which is reagent or product in surface reaction, use being made of phase (synchronous) detection method, where forced low-frequency modulation signal of plasma-shaping generator is used as reference signal. |
 Method and device for monitoring plasma-chemical etching processes using differential optical actinometry / 2248646Real-time monitoring of plasma-chemical etching processes using differential optical actinometry includes mixing of gas-source of chemically active particles and inert gas-actinometer complying with optical actinometry conditions in definite proportion; their supply to reactor chamber followed by measurement of intensities of chemically active particle (chemical agent) emission line in surface reaction and emission line of gas-actinometer in plasma in the course of plasma-chemical etching in plasma-chemical reactor according to algorithm of monitoring actinometric rate-of-layer etching, process selectivity, and end-of-etching moment; in the process mixture of gas-source of chemically active particles and gas-actinometer prepared in advance is supplied to one gas admission channel; used as controlled variable is signal controlling normalization of actinometer emission line intensity at which differential signal between emissive intensities of chemically active agent or particle in surface etching reaction and gas-actinometer on characteristic wavelength from plasma volume tends to zero. |
 Method for grading semiconductor devices / 2251759Proposed method designed for grading semiconductor devices by criterion of their potential reliability both in the course of manufacture and during inspection tests at manufacturing plant includes measurement of low-frequency noise of semiconductor devices at two currents. Potential reliability of device is judged by tangent of tilt angle of curve showing noise intensity as function of current for each device found from equation Estimate criterion is tgαi ≤ tgαcr for high-reliability transistors and tgαi > tgαcr for lower-reliability transistors. The > tgαcr value is found experimentally in the course of grading devices of each type. |
 Method for sorting out semiconductor devices / 2253168Noise-factor is measured on sampled semiconductor device at currents up to 1 mA, ampere-noise characteristics are constructed for maximal and minimal values, current causing highest difference in ampere-noise characteristics is evaluated, and mean noise-factor value is found for given currents. is used for sorting out Lot of instruments is sorted out with respect to their reliability by deviation of noise-factor of each device from mean value at given current. |
 Flaw inspection method for silicon-on-insulator films / 2256256Proposed method used to inspect epitaxial silicon layers grown on insulating substrates for structural perfection includes ellipsometric measurements of film refractive index at different positions of structure adjusted by rotating it about normal to surface; measurement results are used to evaluate coefficient of anisotropy A = 1 - nmax/nmin, where nmax, nmin are maximal and minimal refractive indices, respectively. Degree of film unsoundness is judged by coefficient of anisotropy. |
FIELD: physics.
SUBSTANCE: method of inspecting the quality of a light-emitting diode (LED) structure involves detecting radiation of the LED structure, processing the radiation to obtain characteristics of the LED structure, which are then used to determine the quality of the LED structure, wherein for each LED structure from a batch of items, the electroluminescence spectrum is recorded, the recorded spectrum is constructed in semi-logarithmic scale, the short-wave region of the obtained spectrum is divided into sections which are approximated with a certain relationship, and the approximated sections with maximum and minimum inclination are selected; the maximum and minimum temperature of the LED structure on the selected sections is determined, the average temperature difference value is calculated, the temperature difference value for each LED structure is compared with an average, if the temperature difference value is greater than the average value, the structure is of low quality.
EFFECT: method reduces the cost, enables to use less bulky and cheaper equipment and enables to determine the quality of packaged LEDs, including LEDs in LED-based articles.
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The invention refers to the testing of semiconductor light-emitting diodes (LEDs), namely to a method of detecting the presence of defects in them led structure. This method can be used for quality control led Board structure, including members of the various products on their basis (lamps, displays, matrix) at all stages of production.
There is a method for quality control instrument silicon layers in compositions type silicon on insulator, presented in the patent RF №2150158 "Method of control of defects in silicon films on dielectric substrates", IPC H01L 21/66, publ. 22.02.1999. The method, which can also be applied to determine the quality of the led patterns, includes ellipsometric measurements of refractive index films in conditions of heating the tested structure from room temperature to 350 to 400 K. the nature of the changes defined in the refractive index judge the quality of the films. Before measurements patterns within 1-5 minutes it is treated with ultrasound with frequency 20-40 kHz in chemically inactive liquid. The technical result in the claimed method is because processing structures to ellipsometric measurements leads to the diffusion of impurity atmospheres around defects in silicon film, resulting increases the amplitude of the heterogeneity of other fields of stresses in the film, which determine the increase of the gradient of the refractive index on the film surface, which is fixed by heating (cooling) patterns from room temperature up to the temperature 350-100 K. The method allows to increase sensitivity of ellipsometric control of defects in silicon films on dielectric substrates and led structures SD.
The method is applied method of ellipsometry, which has a relatively low informative value and necessity of use of physical models. This has a destructive character, as it requires pre-treatment of samples led patterns ultrasound, further diagnostics are performed in conditions of high temperatures. Both of these stages may occur corruption of the sample. Used for ellipsometric measurements equipment is relatively expensive and does not allow non-destructive way to explore compositepane led patterns, including members of the products on their basis.
There is a method of continuous katodolyuminestsentsii used for complex diagnostics of parameters, including quality, various materials, in particular led patterns (Solomon V.I. "Luminescent analysis of solids: new opportunities", magazine "Bulletin of Ural Department of RAS, 2008, №2 (24), p.21-27: Chukichev M.V., Sabria D.M., Sokolov V.I. and others "Cathodoluminescence solid solutions Zn 1-Mn x x Se", the journal "Optics and spectroscopy", 1990, volume 68, number 1, s-202). The method consists in the following: sample led patterns bombing fast (primary) electrons, causing the effect of katodolyuminestsentsii. To ensure the continued katodolyuminestsentsii necessary to ensure the flow of the injected into the sample of charge to remove the limitation of luminescence and injection of electrons in matter. As this measure is used by the emission of fast secondary electrons from the surface of the sample in vacuum or effluent charge is carried out through a thin metal layer, put on the irradiated surface of the sample. To implement this method, you want to place the sample led patterns in a vacuum to remove the surface layer of the substance in the thickness of 20 micron, and to provide a high current density of injected electrons And 50-100/cm 2 , the impact of which warms up to the critical temperature of the test sample. Received radiation register the special spectrometers, and further analysis of experimental data allows to detect defects in the led structure.
The disadvantage of this method is its destructive nature and use of expensive equipment (vacuum conditions you want to remove the surface layer of the substance). Used to implement the process of continuous katodolyuminestsentsii equipment does not allow non-destructive way to explore compositepane led patterns, including members of the products on their basis.
The known method of pulse katodolyuminestsentsii (TCL), which can be used for spectral-luminescence analysis of condensed matter to determine their structure and the presence of point defects, in particular for determining the quality led structures (Solomon V.I. "Luminescent analysis of solids: new opportunities", magazine "Bulletin of Ural Department of RAS, 2008, №2 (24), p.21-27). For its implementation it is required to irradiate the sample led patterns of pulses (beams) of high-energy electrons E =100-200 Kev and nanosecond duration. Such electrons penetrate solid substance to a depth d e =100-150 microns, which is greater than the thickness of the surface layer enriched with defects, so in this way there is no need to install the sample in a vacuum chamber and remove its surface layer. Limits on the duration of electrons injection nanosecond intervals leads to elimination of the problem of heating the irradiated volume. The resulting exposure katodolyuminestsentsii register the special spectrometers. In the middle afterglow of katodolyuminestsentsii, even at room temperature samples, there is a fine structure of the bands intracenter population and structural-sensitive ikl. The luminescence centers are point defects led patterns. Definition of quality led patterns is done through the analysis of the obtained spectra of katodolyuminestsentsii.
The disadvantage of TCL is the use of expensive equipment (such as desktop pulse katodolyuminestsentsii spectrograph), which does not allow non-destructive way to explore compositepane led patterns, including members of the products on their basis.
There is a method of diagnostics of semiconductor heterostructures, including led, titled "Method of local katodolyuminestsentsii" (Zamoryanskaya MS, Konnikova YEAR, "New possibilities of x-ray spectrum microanalysis and local katodolyuminestsentsii for the diagnosis of multilayer structures and nanomaterials", journal industrial laboratory. Diagnostics of materials. Special issue", 2005, volume 74, p.62-66). In applying this method a sample of the led patterns bombing by fast electrons, causing the effect of katodolyuminestsentsii. For the formation of the electron beam used column x-ray microanalysis. To obtain spectra local katodolyuminestsentsii stationary mode. In this mode, the sample is continuously irradiated by an electron beam. Scanning of spectra is carried out by the turn of the diffraction grating on the specified steps, followed by a reading of the signal with the photomultiplier tube in the photon counting mode. Subsequent analysis of experimental data among other things allows you to get information about the homogeneity of the sample and determine the spatial distribution of defects in the samples. Features of the size of the energy of bombarding electrons and transmission emitting centres cause strong dependence of brightness of katodolyuminestsentsii to the degree of perfection of the crystal structure of the material. This feature of katodolyuminestsentsii and is used to register the defectiveness of the led patterns. To assess its quality is also possible along the length of electron diffusion.
The disadvantage of this method is the use of an expensive, complicated and cumbersome equipment and impossibility of research of quality of housed led structures, including members of the products on their basis.
1) application of expensive and complex equipment of high resolution;
2) the ability to determine the quality not only of housed led structures.
The task, which directed the claimed invention is a method of quality control led Board structure, which allows to reach the technical result consists in reducing its cost, use, when used less bulky equipment, the possibility of research led patterns of housed SD, including members of the products on their basis.
Essence of the invention consists in that in the way of quality control led patterns, which consists in the registration of the radiation of led patterns, handling radiation for characterizing the led structure upon which to judge the quality of the led patterns for each led patterns of party items, register range of electroluminescence led patterns, carry out construction of the measured spectrum in semi-logarithmic scale, the share of the short-wave region of the received spectrum for the land that approximate the dependence y=a*exp(-bx), where
at - the intensity of radiation,
x - energy photons,
b - coefficient, numerically equal to 1/kT,
a - weighting factor that takes into account the dependence E g (T),
T is the temperature of the led patterns,
E. g - width of the forbidden zone of the active area of the BOD,
and choose approximated areas of maximum and minimum slope, next, determine the maximum and minimum temperatures led patterns on selected sites, determine the value of the difference of temperatures, calculate the mean value of temperature differences, carry out a comparison of the values of temperature differences for each led structure with middle if the value of difference of temperatures is more than the average, makes the conclusion about the low quality structures.
The peculiarity of the proposed method is that changes in the spectra of electroluminescence led patterns caused by impurities, composition fluctuations in the solid solution, fluctuations of the parameters of heterojunctions and parameters of quantum wells, and excitonic effects and transitions in shallow acceptor States, significantly affect the long-wavelength part of the spectrum led patterns and the position of its maximum, while short-wave part of the spectrum of luminescence remains slabocuvstivenami to the aforementioned effects. In the basis of the method of determining the temperature inhomogeneities, allowing to judge the quality of the led patterns, is theory of van Rybreka - Shockley, which allowed transitions zone was obtained expression that describes a range of self-electroluminescence:
F ( ω ) = With ' ( T ) x k ( ω ) x exp ( - h ω 2 PI k T )where E g - width of the forbidden zone of the material, k is the Boltzmann constant, T is the temperature of the active region. The multiplier With a'(T) entered all the values that are not dependent on the photon energy hω. Its value depends on the temperature, the level of excitation (current) and the quantum yield of luminescence. Essentially'(T) can be regarded as normalizing multiplier k (W) of the spectrum of the intrinsic absorption:
k ( ω ) = A h ω 2 PI - E gThe maximum of the spectrum of luminescence zone is located at the energy ћω=E g +kT/2, and the width is proportional to RT.
The quality of the led patterns characterized by defects of the active region, which determines the value of temperature inhomogeneities in it. The higher the defectiveness of the active region led patterns, the greater the probability of nonradiative recombination and lower the brightness of the led patterns. In semi-logarithmic scale, short-wave part of the spectrum led patterns can be a set of direct, the slope of which is determined only RT, i.e. temperature, areas of its active area, where radiative recombination. The presence of different slopes of such sites curves says on nonuniform temperature distribution in the active region led patterns. On heating the active region led patterns of high quality affects mainly the distribution of current in it, so at this led to the structure temperature above in the part of the active region in which more current density. The highest current density in the active region, as a rule, formed under the contact led patterns, so in this part of the structure of an increase in temperature of the crystal, but relatively small in magnitude. If the active area of the defect, the probability of nonradiative recombination in its surroundings will dramatically increase. This will cause significant local overheating of the structure and the size of thermal inhomogeneity will be significantly higher than the quality structure that contains no defects. In the study of party ready led structures temperature difference under the contact, and in the periphery of the crystal is on average the same for all structures of high quality. If the party exists poor quality led structure, the temperature difference in the active region is far above the average. This will allow to detect the presence of a defect in the active region led patterns and identify poor-quality samples in the party is ready LEDs.
Registration of electroluminescence spectra is carried out as follows: radiation testing led structures (including members of the various products on their basis) is going fiber connected to the spectrometer quick scan, in which it, getting on diffraction grating, decomposed by wavelength and is registered silicon CCD. Measurement of one MD and the definition of its defects can be done in a very short period of time (0.1 s or less).
Spectrometers quick scan in comparison with IR microscopes more compact and cheap. For registration of electroluminescence used fiber and spectrometer quick scan, so the method is non-contact and allows you to explore compositepane led patterns, including members of the products on their basis.
Thus, the proposed method is based on the analysis of the spectrum of luminescence led patterns, so it does not require too bulky and relatively expensive equipment, in addition, allows non-destructive way to explore the quality of the active area of the BOD, members of the products on their basis.
The invention is illustrated by the following drawings:
Fig 1. Electroluminescence spectra of two led structures of the party in semi-logarithmic scale in coordinates 1g(I (W) /I (W)max )=f(ћω)).
2. An example of processing of the spectrum at the stages of segmentation into sections and approximation.
3. An example of processing of spectrum for high-quality led patterns.
Figure 4. An example of processing of the spectrum for poor-quality led patterns.
For each led patterns of party conduct:
1) the Measurement of the spectrum of luminescence led patterns, namely:
A. collection radiation test led patternsfiber;
b. decomposition of radiation led patterns on lengths of waves
diffraction grating;
C. registration laid out in the spectrum of radiation led patterns silicon CCD.
2) Construction of the measured spectrum in semi-logarithmic scale in coordinates 1g(I (W) /I (W)max )=f(ћω)).
3) Split the short-wave region of the spectrum to the polling stations.
4) Approximation areas.
5) Choice of two plots with maximum and minimum slope (in semi-logarithmic scale).
6) determination of the maximum and minimum temperatures areas.
7) Determination of temperature differences areas.
8) Determining average temperature differences for party led structures.
9) Carrying out a comparison of temperature differences of each led patterns average.
10) determine the quality of the led patterns.
ExampleAt an operating current of 10 mA measured spectrum of electroluminescence party led structures LEDs spectrometrically instrument with a spectral resolution not lower than 1 MeV (about 0,04 kT) in the range of the signal at least two orders of magnitude from its values at maximum.
The spectra were built in semi-logarithmic scale in coordinates 1g(I (W) /I (W)max )=f(W) (see figure 1). Then the short-wave region of the spectrum was divided into plots. Areas were approximiately expression (see figure 2):
y=a*exp(-b),
where x is the energy of the photons, is the intensity of radiation (UNED), b is the coefficient of numerically equal to 1/kT, a - weighting factor that takes into account the dependence E g (T).
At the specified coordinates with the short wavelength end of the spectrum, ranging from energy photons about 20 MeV above ћω max on the slope of the linear plot, determined the desired temperature selected sites led patterns, according to the formula:
T = 1 b x k , T min = 1 34.5 x 8.5 x 10 - 5 = 341 K = 68 ° C , T max = 1 30.4 x 8.5 x 10 - 5 = 387 K = 114 ° C , Δ T = T max - T min = 114 - 68 = 46 ° C .As can be seen, the difference in temperature of the active region this led is 46 deg C and above average (19 C). We can assume that it is defective.
Thus, the proposed method allows to reduce its cost, use less cumbersome and expensive equipment and to determine the quality of housed LEDs, including members of the products on their basis.
The method of quality control of the led patterns, which consists in the registration of the radiation of led patterns, handling radiation for characterizing the led structure upon which to judge the quality of the led patterns, notable for each led patterns of party products range register of electroluminescence led patterns, carry out construction of the measured spectrum in semi-logarithmic scale, the share of the short-wave region of the received spectrum for the land that approximate the dependence y= a *exp(-bx), where y is the intensity of radiation, x - energy photons, b - coefficient, numerically equal to 1/kT, and - weight coefficient, taking into account the dependence E g (T), T is the temperature of the led patterns, E g - width of the forbidden zone of the active area of diabetes, and choose approximated areas of maximum and minimum slope, next, determine the maximum and minimum temperatures led patterns on selected sites, determine the value of the difference of temperatures, calculate the mean value of temperature differences, carry out a comparison of the values of temperature differences for each led structure with middle if the value of difference of temperatures is more than the average, makes the conclusion about the low quality structures.