The method of determining the rate of growth of semiconductor films and device for its implementation
(57) Abstract:The inventive generator 9 synchronously with the rotation of podarkticules 4 generates pulses that unlocks the gun 5 fast electrons, which generates pulses with a period equal to the period of rotation of the substrate. Receiving optics of electrons registered by the detector 6. The filter 10 highlights from registered by the detector 6 discrete low-frequency signal component that carries information about the changes in the intensity of the diffracted electron beam, which is judged on the growth rate of the semiconductor film. 2 C. p. F.-ly, 3 ill. The invention relates to the growing technology of thin films and can be used in molecular beam epitaxy (MBE) to control the speed of the growth of semiconductor films.One of the major trends of the modern stage of development of physics and technology of semiconductors is more extensive study and application of semiconductor thin film structures with hyperfine components of the layers produced by the MBE method, for example, heterostructures, and superlattices. Further progress in the technology of MBE due to the capabilities of the playback growing uniform is For reproducible cultivation must be provided with operational control of the rate of growth of the film over the entire area of the substrate at the level of 1 monolayer/s The homogeneity of the properties and thickness of the grown layer on the area of the substrate provides a process MBE on a rotating substrate.There is a method of measuring the rate of epitaxial growth of semiconductor films, which consists in irradiating the surface of the film growth of high-intensity beam of light quantum energy near threshold photoemission and the measurement of the oscillation period of the photoemission current from the illuminated surface of the epitaxy  .One oscillation period of the photoemission current corresponds to the build-up on the surface of a semiconductor single monolayer of atoms. If the duration of one oscillation period of T, then the rate of growth of Vp= 1/T the monolayer/C. This method allows you to measure the speed of MBE growth on a stationary substrate or in the center of the rotating substrate.The disadvantages of the described method is the difficulty of measuring the growth rate distribution on the surface of the fixed substrate associated with the need for Ostrovityanova, high-intensity short-wavelength optical beam is moved over the surface of the substrate. In the case of the rotating substrate is measured in the center of the substrate due to the interfering signal, obuslovlennogo the fair adsorption of impurities from the atmosphere, the residual gases of the vacuum chamber installation MBE.Closest to the invention is a method of measuring the rate of growth of semiconductor films, which consists in the irradiation surface growth by a fast electron beam, detecting reflected from the surface of the growth dimagiba - tion of the electron beam and the measurement of the oscillation period of the electric signal resulting from detection  .A device for implementing the known method is a vacuum chamber with molecular springs, dampers and podarkticules with the substrate, which has a cannon of fast electrons, connected to the control unit, and a detector of the reflected electron beam (for example, a fluorescent screen and a photodetector), and cannon and a detector positioned relative to the substrate so that the electron beam falls on the surface of growth under grazing angle and provides the conditions Wolfe-Braggot, and the reflected receiving optics of the electron falls to the input of the detector (image of one of the reflexes of the pattern of diffraction of fast electrons (the RHEED) on the fluorescent screen is converted by the photodetector into an electrical signal, proportional to the intensity of the reflected electron beam). Output dete the electronic beam, and therefore, the signal at the output of the detector oscil - lerouet with period T equal to the time extension of one monolayer of atoms of the semiconductor. The growth rate is the same as in the first method of measuring, by using a recording unit (which can be used recorder, a digital oscilloscope or computing device).The disadvantages of this method and device are limiting the field of application, due to the impossibility of measuring the growth rate on the surface of a rotating substrate (as in the rotation of the substrate irradiated by a beam of fast electrons are all different parts of the growing film), and contamination of the grown films associated with uncontrolled introduction of impurities (oxygen and carbon) in place of the radiation from the atmosphere of the residual gases of the vacuum chamber installation MBE,
The purpose of the invention is the expansion of the scope of the method by providing a measure of the rate of growth on a rotating substrate and improving the quality of the grown structures by reducing the uncontrolled introduction of impurities in the growing layers in the measurement process.This is achieved by a method for measuring the growth rate of polypr the processes reflected from the surface of the growth of the diffracted electron beam, the measurement of the oscillation period of the electric signal obtained by detecting and determining from the measured period of the growth rate of the film, the exposure surface of the film growth produce a pulse with a period equal to the rotation period of the substrate, in the moments corresponding to the ingress of a beam of fast electrons on a controlled surface area growth of a rotating substrate, and the electric signal is limited by the width of the frequency spectrum range F = 0; Fband pulse duration of exposure tuand the cutoff frequency Fbchoose terms and conditions:
Fb= Vpmaxwhere d is the width of the reflected from the surface of the growth of the electron beam in the plane of detection;
l is the distance from the center of the substrate to the plane of detection;
Vpmax- maximum speed of film growth.The device for implementing the method, containing a vacuum chamber placed in her molecular sources with butterfly podarkticules with the substrate, gun fast electrons, connected to the control unit, and a detector of the reflected diffracted electron beam connected to the block moderately, and the return to the gun fast electrons, and a lowpass filter input connected to the output of the detector, and the output connected to the input of the recording unit.In Fig. 1 shows a functional diagram of the device of Fig. 2 - the time dependence of the intensity Iethe reflected diffracted beam; Fig. 3 - change in time of the voltage signal Uwithafter filtering.The method is as follows.Surface growth in a given place of the rotating substrate is irradiated by a beam of fast electrons in discrete moments of time corresponding to the conditions of the wolf-Braggot. The time dependence of the intensity Iethe reflected diffracted electron beam and its corresponding electrical signal after detection is in this case a sequence of pulses, the low-frequency component of the spectrum which carries information about the rate of growth as in the case of continuous irradiation surface growth.Obtained by detecting an electrical signal in discrete form limit on the width of the frequency spectrum, resulting in it is converted to continuous The growth rate is determined by the formula:
Vp= , where T is the period of oscillation of a continuous electrical signal measured after filtering.The pulse frequency of the radiation is determined on the basis of the sampling theorem (4), which determines the condition for exact recovery of the continuous signal, represented by its reference in discrete moments of time. In particular, for a precise reconstruction of the sinusoidal signal with a period of T samples should be taken at least 2 times per period of oscillation. Therefore, at a maximum speed of Vpmaxthe sampling rate and, hence, the frequency f of the pulses of radiation must satisfy the condition
The value of Vpmaxhas physical limitations, deriving from the principle of MBE, and is determined by the particular design of the particular installation MBE - diameter substrate, and distance her from molecular sources. The value of VR.maxusually no more than ~ 1 .Thus during rotation of the substrate at any point on the substrate conditions of diffraction can be performed at least once per rotation of the substrate, therefore, the rotational speed of the substrate fBPmust be equal to the pulse frequency of the radiation, so the situation substrate the reflected receiving optics crosses the reception area of the detector electrons, and which is determined on the basis of the angular speed of rotation of the substrate = 2nfBP, the distance l from the center of the substrate to the receiving area of the detector, the width d of the reflected electron beam in the plane of detection (the width of the receiving area of the detector in the azimuthal plane we assume equal to the width of the reflected electron beam), in other words, the duration of tupulse is defined as the time when the rotation of the substrate with angular velocity = 2 fBPthe end of the reflected electron beam on the landing of the detector will make a way in an arc of radius l equal to twice the width of the reflected electron beam (twice the width of the reflex in the picture of the RHEED); tu= or tu. (2) the Lower limit for the pulse duration of exposure tulimited sensitivity and speed detector of electrons.The device for implementing the method (Fig. 1) includes a vacuum chamber 1 with its molecular sources 2, the flaps 3, podarkticules 4 with the substrate, cannon 5 fast electrons and the detector 6 of the reflected diffracted beam. To the cannon of fast electrons is connected, the control block 7, polictial - clock input 8 output coloroado detector 6 is connected in series connected filter 10 of the lower frequencies and the block 11 of the Desk.The device operates as follows. After predmostovoy preparation of the substrate enables the rotation of podarkticules 4 and is opened to start the growth of the flap 3. The synchronizer 8 associated with podarkticules 4 (optically or mechanically, etc.,) at points in time corresponding to the penetrating beam of fast electrons on a controlled surface area growth, once per rotation of the substrate generates the synchronization signals, which are fed to the input of the pulse generator 9. The latter synchronously with the rotation of podarkticules 4 generates pulses that unlocks the gun 5, which at discrete points in the selected location of the substrate irradiates the surface of the growth of the fast electron beam.Reflected dragirovaniya electron beam (corresponding to the reflex of the RHEED pattern on the fluorescent screen) at the moment of action enabling pulse reaches the input of the detector 6. since the output of which is a discrete electrical signal to the input of the filter 10 of the lower frequencies, which converts the signal from the discrete to the continuous form. The output signal from the lowpass filter to the input of the recording unit, by which the period of oscillation of the continuous signal measured by the growth rate.to maintain an electrical signal. In accordance with the Nyquist theorem (4) its cut-off frequency is selected:
Fin(g)= Vpmaxwhere Vpmax- the maximum rate of growth during epitaxy.Setting installation options MBE:
Vpmax= 1 ,
l = 250 mmd = 1 mmFind:
exposure f 2VR. max< / BR>Choose f = 3 (-1)
gates fBP= f = 3 (-1)
exposure tu= = 0,410-3(3)
the lower frequency Fb= V.max.= 1 (Hz)
growth of ml-
aqueous monolayer Tmin= = 1 (c)
The duration of the pulse of radiation is only a small part time capacity of one monolayer
= = 810-4(4)
Therefore, the impact of the introduction of impurities from the atmosphere, the residual gases of the vacuum chamber MBE on the quality of the grown semiconductor in place of the radiation decreases.Thus, the proposed method and device for measuring the rate of growth of epitaxial films allow for the expense of pulse irradiation surface Rossa in growing layers in the measurement process ultimately, improves the quality of the grown epitaxial thin-film structures. 1. The method of determining the rate of growth of semiconductor films in the process of building on a substrate, which consists in irradiating the surface of the growing film by a fast electron beam, detecting reflected from the surface of the growth of the diffracted electron beam, the measurement of the oscillation period of the electric signal at the output of the detecting device and determining from the measured period of the growth rate of the film, characterized in that, to ensure measurement of the rate of growth of the film by rotating the substrate and reduce the uncontrolled introduction of impurities in the growing layers in the measurement process, the irradiation surface growth provide a pulse with a period equal to the rotation period of the substrate, the electrical signal at the output of detecter filter, restricting the width of the frequency spectrum range F = 0; Finand pulse duration of exposure tandand the cutoff frequency is chosen terms and conditions
tand; Fin= v, ,
where d is the width of the reflected from the surface of the growth of the electron beam in the plane of detection;
l - distance from the city centre 2. A device for determining the rate of growth of semiconductor films in the process of building on a substrate containing a vacuum chamber, which has a molecular springs with dampers, polictial, gun fast electrons, connected to the control unit, and a detector of the reflected diffracted electron beam connected to the recording unit, characterized in that it is provided with a synchronizer associated with podarkticules, pulse generator, whose input is connected to the synchronizer, and the return to the gun fast electrons, and the low pass filter, whose input is connected to the output of the detector, and the output is connected to the recording unit.
FIELD: investigating or analyzing materials.
SUBSTANCE: focusing monochromator comprises rectangular plate made of metal provided with parallel stiffening ribs arranged over the width of the plate. The faces of the stiffening ribs are provided with reflecting plates made of monocrystal.
EFFECT: reduced cost.
FIELD: examination of baggage; customs inspection.
SUBSTANCE: according to the method, the object should be inspected inside one local area G (m). Detection unit is divided to lower and higher degrees of inspection. Coordinates of local area are determined at lower degree of inspection; electron diffractometer is oriented to the local area at higher degree of inspection. Explosives can be detected, for example, by using x-ray diffraction analysis. Electron diffractometer has collimating-detection system, which can be regulated, in height and in side direction at higher degree of inspection. Diffractometer also has X-ray radiation source, which is matched with collimating-detection system, which can be oriented at side direction. Collimating-detection system has one collimator max and one detector. Collimator is provided with conical widened slit, which reproduces preset angle Θ of dissipated radiation.
EFFECT: higher speed of detection of prohibited luggage.
14 cl, 6 dwg
FIELD: radiation methods of testing.
SUBSTANCE: tested object is subject to illumination of narrow low-divergent beam of penetrating radiation and radiation passed through object is registered by means of coordinate-sensitive detectors. Structure of matters composing the object is identified from small-angle coherent dissipation of radiation passed through object. Distribution of radiation intensity across the beam is registered when object is present and absent correspondingly. Attenuation factor of penetrating radiation is determined for center of the beam by means of comparing intensities of incident beam and passed beam. Intensity distribution curve is normalized for incident radiation at the area of central peak of diffraction for angle of dissipation by attenuation factor and is subtracted from curve of distribution of radiation passed through the object.
EFFECT: higher quality of building of internal structure of object.
1 tbl, 1 dwg
FIELD: measurement engineering.
SUBSTANCE: sample of saturated thickness tested material is irradiated by monochromatic gamma-ray or X-ray radiation and intensities of coherent dissipated primary radiation of matter being non-coherent dissipated. Concentration of element in tested sample is calculated from analytical signal which has to be the relation of mentioned intensities registered simultaneously or subsequently.
EFFECT: improved precision of measurement.
FIELD: investigating or analyzing materials.
SUBSTANCE: device comprises collimating-detecting system that is made controllable in height with respect to the source of Roentgen radiation. The system and source are adjustable in longitudinal and transverse directions. The collimating-detecting system is provided with single collimator and detector. The collimator has conically diverging circular slot, which reproduce a given angle of the light path of diffusion radiation.
EFFECT: increased rate of detecting.
FIELD: quantitative and qualitative elemental analysis.
SUBSTANCE: objects are subjects by probing gamma-quantum irradiation with E0 energy and energy distribution of gamma-quanta is measured, dissipated according to Compton-effect on bound electron in mode of time coincidence mode with X-ray photons from K-set. First the list of elements to be analyzed is chosen according to ascend of atom number Z1<Z2, <...<Zn and list of binding energy of K-electrons, corresponding to that one, E(Z1)<E(Z2)<...E(Zn) and sequent ranges of angles of dissipation Δφ1, Δφ2,... Δφn of probing quanta are measured, inside which angles the quanta dissipate after K-vacancy is excited from one additional K-set of list E(Z1)<E(Z2)<...E(Zn) into each range. Then detectors for registration of dissipated gamma-quanta are placed into any that range. Amplitude of signal from range is subject to amplification and normalization independently. Results of simultaneous adding of normalized amplitudes with amplitudes received from detector are stored, which amplitudes were received from detector that registers X-ray photons of different K-sets. Selectivity of simultaneous registration of X-ray photon and of photon, dissipated according to Compton-effect mechanism, allows identifying atom numbers of elements. Concentrations of elements to be found in tested object are determined from results of simultaneous summing.
EFFECT: non-destructing multi-elemental analysis under high radiation background.
2 cl, 4 dwg
FIELD: devices and methods for determining orientation of crystallographic plane relatively to crystal surface, and also device and method for cutting mono-crystal in cutting machine.
SUBSTANCE: in accordance to method, angle, formed between crystal surface being measured and base axis, is measured, and angle, formed between crystallographic surface and base axis, and measured angles are subtracted. Then, in device for wire sawing, containing X-Y adjustment device, required correction is performed by measuring orientation and at the same time crystal is moved in horizontal and vertical positions. As a result, additional degree of freedom remains for rotation of crystal in cutting plane to achieve cut, unaffected by forces, perpendicular to feeding direction and wire direction, so that tool deflection is absent, or cutting forces are minimal.
EFFECT: increased cutting precision, and simultaneously increased output of plates during mono-crystal cutting.
4 cl, 12 dwg
FIELD: the invention may be used for controlling quality of articles out of hard alloys after radiational-thermic processing.
SUBSTANCE: the mode is in that the sample is impacted with x-ray radiation for registering its diffracting spectrum, definition of the concentrations of carbide phases - of monocarbide of tungsten WC and compound carbide (Ti,W)C- in a hard alloy of the composition WC-TiC-Co, definition of physical broadening (β) of two patterns of reflection from one aggregate crystallographic planes that is β1 and β2 and an angular positions of centers of the whole weight (θ) of selected lines that is θ1 and θ2, control of quality of the articles after radiational-thermic processing, in defining the coefficient of resistance of articles out of hard alloys after radiational-thermic processing, conditions of counting the value of integral disordering of the carbide phases and disordering of monocarbide WC relatively to the given values.
EFFECT: estimation of quality and unique forecasting of the term of service of articles subjected to radiational-thermic processing and simplification of the mode.
FIELD: the invention refers to the field of investigating liquid samples with the aid of an x-ray beam.
SUBSTANCE: the essence of the mode is that controlling of an x-ray beam is executed with the aid of successive reflection of a preliminary monochromatized beam of a synchrotron emission from two mirrors with a cylindrical and a plane surfaces and rotation of the second mirror around its axle normal to the plane of scattering of x-ray rays. At that rotation of the first mirror around its axle is carried out normal to the plane of scattering of x-ray beams. At that the angle θ1 between the beam and the first mirror and the angle θ2 between the beam and the second mirror are tied by a definite ratio.
EFFECT: provides invariability of the field of illumination of the horizontally located surface of the investigated liquid sample at various values of the angle between the x-ray beam and the surface of the sample.
SUBSTANCE: diffractometer comprises base, analytic instrument, source of radiation beam, radiation beam detector, means for moving the analytic instrument in space, cantilever for supporting the analytic instrument that is mounted for permitting rotation, means for rotation of the source and detector around the center of the diffractometer so that the axes of the beams of the source and detector of radiation lie in the equatorial plane, and structure for moving the analytic instrument.
EFFECT: enhanced precision.
15 cl, 5 dwg
FIELD: semiconductor technology; production of microelectronic devices on the basis of substrates manufactured out of III-V groups chemical element nitride boules.
SUBSTANCE: the invention is pertaining to production of microelectronic devices on the basis of substrates manufactured out of III-V groups chemical element nitride boules and may be used in semiconductor engineering. Substance of the invention: the boule of III-V groups chemical element nitride may be manufactured by growing of the material of III-V groups the chemical element nitride on the corresponding crystal seed out of the same material of nitride of the chemical element of III-V of group by epitaxy from the vapor phase at the speed of the growth exceeding 20 micrometers per hour. The boule has the quality suitable for manufacture of microelectronic devices, its diameter makes more than 1 centimeter, the length exceeds 1 millimeter, defects density on the boule upper surface is less than 107 defects·cm-2.
EFFECT: the invention ensures manufacture of the microelectronic devices of good quality and above indicated parameters.
102 cl, 9 dwg
FIELD: non-organic chemistry, namely triple compound of manganese-alloyed arsenide of silicon and zinc arranged on monocrystalline silicon substrate, possibly in spintronics devices for injection of electrons with predetermined spin state.
SUBSTANCE: electronic spin is used in spintronics devices as active member for storing and transmitting information, for forming integrated and functional micro-circuits, designing new magneto-optical instruments. Ferromagnetic semiconductor hetero-structure containing zinc, silicon, arsenic and manganese and being triple compound of zinc and silicon arsenide alloyed with manganese in quantity 1 - 6 mass % is synthesized on substrate of monocrystalline silicon and has formula ZnSiAs2 : Mn/Si. Such hetero-structure is produced by deposition of film of manganese and diarsenide of zinc onto silicon substrate and further heat treatment of it.
EFFECT: possibility for producing perspective product for wide usage due to combining semiconductor and ferromagnetic properties of hetero-structure with Curie temperature significantly exceeding 20°C and due to its compatibility with silicon technique.
3 ex, 2 dwg
FIELD: electronic engineering; materials for miscellaneous semiconductor devices using gallium arsenide epitaxial layers.
SUBSTANCE: intermetallic compounds chosen from group incorporating tin arsenide SnAs, palladium antimonide PdSb, manganese polyantimonide Mn2Sb, nickel stannate Ni3Sn2, nickel aluminate Ni2Al3, nickel germanate Ni2Ge, and cobalt germanate Co2Ge are used as materials of substrates for growing gallium arsenide epitaxial layers.
EFFECT: enhanced structural heterogeneity of gallium arsenide layers being grown.
SUBSTANCE: invention relates to vacuum technology and the technology of making carbon nanotubes, such as carbon nanotubes at ends of probes, which are used in probe microscopy for precision scanning. The method of making probes with carbon nanotubes is realised by depositing carbon films with nanotubes through magnetron sputtering in a vacuum at direct current of 100-140 mA using a carbon target with a nanotube growth catalyst. Work pieces of the probes are put into a vacuum installation. A carbon film with nanotubes is then sputtered in a residual atmosphere of inert gas.
EFFECT: invention allows for obtaining probes with carbon nanotubes, lying perpendicular the surface of the probe, in required amounts without using explosive substances and complex devices.
SUBSTANCE: invention can be used in manufacturing organic light-emitting diodes, liquid-crystal displays, plasma display panel, thin-film solar cell and other electronic and semi-conductor devices. Claimed is element, including target of ionic dispersion, where said target includes processed MoO2 plate of high purity. Method of such plate manufacturing includes isostatic pressing of component consisting of more than 99% of stoichiometric MoO2 powder into workpiece, sintering of said workpiece under conditions of supporting more than 99% of MoO2 stoichiometry and formation of plate which includes more than 99% of stoichiometric MoO2. In other version of said plate manufacturing component, consisting of powder, which contains more than 99% of stoichiometric MoO2, is processed under conditions of hot pressing with formation of plate. Method of thin film manufacturing includes stages of sputtering of plate, which contains more than 99% of stoichiometric MoO2, removal of MoO2 molecules from plate and application of MoO2 molecules on substrate. Also claimed is MoO2 powder and method of said plate sputtering with application of magnetron sputtering, pulse laser sputtering, ionic-beam sputtering, triode sputtering and their combination.
EFFECT: invention allows to increase work of output of electron of ionic sputtering target material in organic light-emitting diodes.
16 cl, 5 ex
SUBSTANCE: in method for growing of silicon-germanium heterostructures by method of molecular-beam epitaxy of specified structures due to silicon and germanium evaporation from separate crucible molecular sources on the basis of electronic-beam evaporators, silicon evaporation is done in automatic crucible mode from silicon melt in solid silicon shell, and germanium is evaporated from germanium melt in silicon insert, which represents a previously spent hollow residue, produced as a result of silicon evaporation in automatic crucible mode, and arranged in crucible cavity of cooled case of crucible unit of electron-beam evaporator used to develop molecular flow of germanium. At the same time process of epitaxy is controlled with account of germanium deposition speed selection, determined from given dependence.
EFFECT: increased stability and expansion of assortment of generated high-quality silicon-germanium heterostructures as a result of improved control of molecular-beam epitaxy of heterostructures due to accurate control of silicon and germanium deposition mode in the optimal range of speed values, reduction of concentration of uncontrolled admixtures in heterostructures produced by proposed method, and reduction of resource expenditures for preparation of process equipment.
2 cl, 3 dwg
SUBSTANCE: invention relates to the field of nanotechnologies and may be used to form nanostructures from evaporated microdrop by exposure to acoustic fields. Complex for formation of nanostructures comprises a nanostructures shaper, an optical microscope, a data display facility and information processing and complex control facility. The nanostructures shaper comprises a foundation and a source of shaping action, at the same time the foundation is formed as piezoelectric with the possibility to apply initial substrate on its surface, and the source of nanostructure-shaping action is represented by surface acoustic waves (SAW), besides, to develop a SAW line, a pair of interdigital transducers (IT) is located on the piezoelectric foundation with the possibility to excite the acoustic field between them, and the shaper is installed in the object area of the optical microscope, at the same time the axis of the microscope sighting is aligned relative to the foundation at the angle φ, besides, the complex also includes a generator of high-frequency oscillations and a wideband amplifier connected to it and to IT.
EFFECT: provision of universality as regards a class of objects exposed to nanostructuring.
12 cl, 1 dwg, 1 tbl
SUBSTANCE: invention relates to the field of nanotechnologies and may be used to make ordered nanostructures, used in micro- and nanoelectronics, optics, nanophotonics, biology and medicine. The proposed method may be used to manufacture single-layer and multilayer nanostructures, also the ones containing layers of different composition, and also two-dimensional, three-dimensional ordered structures of various materials. According to the method, the substrate and the initial substrate, containing nanoparticles, are arranged to form a space between them. The substrate is sprayed in the specified space in the form of a cloud of drops, every of which contains at least one nanoparticles. Creation of a substrate in the form of a sprayed cloud of drops is done by means of ultrasound exposure, when the source of ultrasound effect is located relative to the substrate with the possibility to arrange a sprayed cloud of drops in the specified space. Control of motion in the specified space and drops deposition onto the substrate is carried out through their exposure to external electric and/or magnetic fields.
EFFECT: wider class of materials, which could be used to form ordered nanostructures, higher accuracy of nanoobjects reproduction, stability of nanostructures formation process in one technological space.