The method of neutron transmutation doping of silicon
(57) Abstract:Usage: in the technology of semiconductor materials for electronic devices and electrical industry. The invention is: to increase the utilization of neutrons in the way neutron transmutation doping of silicon, comprising the reciprocating movement of the containers with ingots of silicon through the exposure zone of the reactor channel and control averaged over the length of the bars of neutron fluence to set the desired fluence, simultaneously moving at least two containers. When changing direction in the exposure zone should be at least one container. When multiple moving in the exposure zone at the point of change of direction there is only one extreme of the container, and the irradiation process interrupt when set at the container half-fluence correct and change containers in places, keeping each of them the same orientation in the channel. In a single move the desired result is reached due to the fact that the container is exposed in this cycle, move with different velocities Vpis the speed with which protray the containers are moved between the overload range and area exposure, moreover, V/Vp2/, where the maximum allowable variation in the concentration transmutation impurity phosphorus in relative units. 2 C. p. F. - ly, 1 Il. The invention relates to a manufacturing technology of semiconductor materials for devices of electronic and electrical industries.Technology neutron transmutation doping (NTD) of silicon-based nuclear reaction
30Si(n )31Si31P (1) as a result of which eventually formed the core dopant is phosphorus. The distribution of these nuclei follows the distribution of the fluence of thermal neutrons by volume of silicon ingots. Usually in technology NTL silicon demands to uneven alloying - 3-5% or less. If the container with silicon under irradiation stationary relative to the radiation field (static mode), then its length, which is achieved by the non-uniform doping, several times or even ten times) less than the linear size of the active zone. Therefore, industrial reactors with large sizes of the active zone (a few meters), in static mode to irradiate containers with silicon length of 0.5 m or more. At regime cannot be irradiated, since the linear dimensions of the active area is less than one meter. In regard to research reactors in the process of irradiation of long containers or otherwise move relative to the irradiation zone to achieve acceptable uniformity of doping.The known method NTL silicon  , including moving through the channel of a nuclear reactor at a constant speed continuously successive containers large extent with ingots of silicon. In this way the containers are loaded in the reactor channel from one side and unloaded from the other.The most important and serious the advantage of this method is almost the full amount of the irradiation zone in the channel doping of silicon. If we ignore the gap between the silicon in the neighboring containers, it turns out that the entire volume of the channel and its radiation areas occupied by silicon. However, this method can be implemented only on a channel of the reactor, which can be accessed from both ends.Known Tacke way NTL silicon  , selected as a prototype, including the reciprocating movement of the channel of the reactor through the exposure zone of the container with ingots of silicon, the control averaged over the length of the useful new and replacement containers. In this way the container is moved in both forward and reverse napravleniya until its useful volume is not completely beyond the area of exposure. Therefore, at each intersection of the irradiation zone all the elementary volumes of the bars are exposed to neutrons with the same fluence
Fi= (x)dx (2) where fi- neutron fluence accumulated in the i-th intersection of the irradiation zone; X1, X2- coordinates at the beginning and end of the irradiation zone; (x) - raspredelenie flux density of thermal neutrons; Vi- the speed of the container when the i-th intersection of the irradiation zone. The coordinates of the irradiation zone X1and X2chosen so that outside these coordinates irradiation ingots neutrons is negligible. In this way, at each intersection of the irradiation zone, the speed of travel of the container must be a constant, but its value can be changed when you change the direction of motion. When the reciprocating movement of the container through the exposure zone monitor neutron fluence, dialed useful volume of the container. As soon as it becomes equal to the desired, irradiation ceased. For this purpose, the container is removed from the irradiation zone and move to the place of transshipment of containers. In this way Proc. of the container technically rational to make use of one mechanism overload.However, in this method, the utilization factor of the neutron radiation field is much smaller than in the method according to the similar.In the method NTL silicon, comprising the reciprocating movement of the container with ingots of silicon on the reactor channel through the exposure zone and the control averaged over the length of the ingot container fluence of neutrons to set the desired fluence, through the exposure zone move at least two containers, when you change the direction of movement of the containers in the area of irradiation is at least one of the containers, and after one or more cycles of moving the irradiation process is interrupted and are replaced containers seats or replacement of at least one of them.When multiple moving at the time of changing the direction of movement in the zone of irradiation is placed only at one extreme, the container, after the set of extreme containers half-fluence correct the irradiation process interrupt, change extreme containers in places, keeping each of them reorientation in the channel, after which the irradiation process continue.In a single move in each cycle the containers to move with velocity vpthrough the exposure zone to the first container, for the remaining containers new place, following the movement of containers lead with velocity v to align the second container with its location in the previous cycle of irradiation at the time of the change of direction, after which the cycle of repeat exposure, and
V/Vp2/, (3) where the maximum allowable variation in the concentration transmutation impurity phosphorus in relative units.The drawing schematically shows the channel reactor radiation zone, and the location of containers (conventionally shown is not the actual containers, and their useful - ingots - volumes) in the extreme positions when multiple (a - d) and a single (d - C) reciprocating movements.When the process is irradiated with at least two containers with bullion (in the drawing, three containers), moving them back and forth through the exposure zone. Moreover, the amplitude of the move set so that the area of exposure when changing direction (positions a, b, C, g, with the repeated movements, the position e or C - in a single move) is present at least one container. In this method, the irradiation process is optionally interrupted before it is dialed to the desired neutron fluence on aout from one extreme position containers (position a) to another (position b) and back. After the extreme containers I and III will be called half-fluence correct, the additional irradiation is interrupted, i.e., all containers return to their place of overload. At the place of loading at the containers I and III of changing places, keeping each of them orientation in the channel. Then the containers are returned to the extreme (reciprocating movement) position (position) and continue to irradiation by moving the containers between the extreme positions (positions C and d). After extreme containers rest half fluence, they are replaced by new ones and continue the exposure.When each radiation between containers pose such a gap that the distance from the center of the useful volume of each extreme of the container I and III to the useful volume of the adjacent container II was not less than half the length of the irradiation zone. If the extreme length of the container is not less than the length of the irradiation zone, the gap between it and the adjacent container may be missing.Containers reciprocating move from one extreme position to the other and back to align the center of the useful volume of the outer container with the center of the irradiation zone, i.e. in positions a and g with the center of Vratna-directional movement of containers at they end up evenly along the length will be irradiated with the required fluence of neutrons.Extreme containers can have the same or different length of useful volumes that are greater than or less than the length of the irradiation zone. For example, the length of the useful volume of the container I is less than the length of the irradiation zone, and the container III is greater than the length of the irradiation zone. Scroll in the container I point MIsuch that it is separated from the center of the useful volume of the container at a distance of X. Then in the position of a point MIhas the coordinate X such that X1X X2where X1and X2the coordinates of the boundaries of the zone of irradiation. When moving from a and b or from point MIpasses through the exposure zone of the path from X to X2. When moving from the position in the city or back point MIpasses through the exposure zone of the path from X1to X. If the containers reciprocating move with the same speed n times when typing the first half of the fluence and n times in the set of the second half, the point MI2n completely cross the whole area of the irradiation. Since all other points in position and located between the X1and X2they also 2n completely cross the whole area of the irradiation and will be irradiated by neutrons with the same fluence. Exactly the same fluence as the container I will be irradiated all points containeryou point M2the coordinate of the position b is less than X1. For the first n cycles of reciprocating motion, she never falls into the zone of irradiation. But for the next n cycles (from the position in g and Vice versa) she 2n completely crosses the radiation zone, i.e., is irradiated by neutrons with the same fluence. Exactly the same fluence in the end is any point of M3the coordinate of the position b is greater than X2: for the first n cycles she 2n completely crosses the radiation zone, and for the next n cycles it will not enter the radiation zone.As to the middle of the container II, each moving in the forward or reverse direction all his points are fully exposed. In one such move, he gathers evenly along its length fluence, defined by the expression (2). Its length can be any. Moreover, such (medium) containers may be few and they will be for the i-th move uniformly irradiated by neutrons with fluence in the expression (2). After secondary containers will dial the desired neutron fluence, the containers are moved to the loading site, replace the secondary containers for new and continuing the irradiation. The breaks in the irradiated medium containers mobitelom the movement of their containers move through the zone of irradiation (from position d to position e) as long while one of them (container I) is not completely beyond the area of exposure. When the containers are moved from position d in e such estimated velocity vpto each container after complete intersection zone radiation was irradiated by neutrons with the required fluence fopt. Therefore, after the first move the useful volume of the container I is uniformly irradiated by neutrons with the required fluence
Fopt= (x)dx. (4) Then the containers with velocity v is larger than vpreturn to the loading site. The containers I and II trying to enter additional neutron fluence. The container I completely crosses with velocity v the exposure zone. So it evenly along the length of gaining additional fluence
Fd= (x)dx, (5) which take into account when getting in the nominal doping. The container II is not completely crosses the radiation zone, so additional fluence along its length is distributed unevenly. The maximum possible irregularity occurs when one end of the container II is fully crosses the area of exposure and gaining additional fluence (5), and the second end is additionally not irradiated by neutrons. Therefore, the difference between the additional fluences will be no more, escaut for the remaining. When the second reciprocating cycle of irradiation containers move with velocity v to match the first (container II) its location in the previous cycle of irradiation at the time of changing the direction of motion (item W). The dierence additional fluences at the ends of the container II doubles
Fd(x)dx. (6) From the position W of the containers moving with velocity vpup until the useful volume of the first (container II) is not completely beyond the area of exposure (position C). Then the containers return with velocity v to the loading site, and recruit additional fluence on the container II also take into account how and when the irradiation container I to hit the nominal doping. Thus, the container II with an estimated speed v only once completely crosses the zone of irradiation. The dispersion concentration of the transmutation of an impurity of phosphorus is determined by the range of additional fluence of neutrons = (7) subject to (2) and (6)
2 . (8)
All other cycles of exposure do not differ from the second.The irradiation of both the proposed method and the prototype of the number of fully irradiated containers is equal to the total number of breaks in the irradiation. At the same time, the second exposure is constantly present in the irradiation process at least one container with ingots of silicon. (56) 1. Smirnov, L. S. Solov'ev, S. P. , Stas C. D. and other Doping of semiconductors by means of nuclear reactions. Novosibirsk: Nauka, 1981, S. 138.2. Neutron transmutation doping of semiconductors. Edited by j. Meese. M. : Mir, 1982, S. 104-122. 1. The METHOD of NEUTRON TRANSMUTATION DOPING of SILICON, comprising the reciprocating movement of the container with ingots of silicon on the reactor channel through the exposure zone and the control averaged over the length of the ingot container fluence of neutrons to set the desired fluence, characterized in that through the exposure zone move at least two containers, when you change the direction of movement of the containers in the area of irradiation is at least one of the containers, and after one or more cycles of moving the irradiation process is interrupted and are replaced containers seats or replacement of at least one of them.2. The method according to p. 1, characterized in that the point of change of direction in the exposure zone only one place, at the container, after the set of extreme containers half-fluence correct the irradiation process interrupt, change extreme containers in places, keeping each of them remains the orientation the containers first move with velocity vpthrough the exposure zone to the outside of the first one, then return the containers with velocity v to the place of their replacement, remove the first container, the remaining containers are placed the following new and moving containers are to pause v to align the second container with its location in the previous cycle of irradiation at the time of the change of direction, after which the cycle of repeat exposure, and v/vpwhere vp- the speed at which moving the container through the exposure zone of the container is irradiated by neutrons with the required fluence, > maximum allowable variation of the concentration of transmutation impurities of phosphorus, Rel. unit
FIELD: production of solar batteries, integrated circuits and other semiconducting devices.
SUBSTANCE: the invention presents a method of production of alloyed monocrystals or polycrystals of silicon and may be used in production of solar batteries, integrated circuits and other semiconductor devices. The substance of the invention: the method of SUBSTANCE: the invention presents a method of production of alloyed monocrystals or polycrystals of silicon includes preparation of the initial charge consisting of 50 % of silicon alloyed with phosphorus with a specific electrical resistance of 0.8-3.0 Ohm·cm or boron with specific electrical resistance of 1-7 Ohm·cm, its melting-down and consequent growing of crystals from the melt, in which additionally enter elements of IV group from the periodic table by Mendeleyev, in the capacity of which use germanium, titanium, zirconium or hafnium use in concentrations of 1017-7·1019 cm-3. The invention allows to produce chips with high values of life time of minority carrier (LTMC), high homogeneity of electric resistivity (ER) and high concentration of oxygen, with a low concentration of defects and increased thermostability and radiation resistance.
EFFECT: the invention ensures production of chips with high values of LTMC, high homogeneity of ER and high concentration of oxygen, with a low concentration of defects and increased thermostability and radiation resistance.
2 cl, 4 ex, 1 tbl
FIELD: devices for continuous grouped growing of the orientated layers of silicon on a carbonic fabric.
SUBSTANCE: the invention is pertaining to the field of growing of polycrystallic layers from a melt of silicon and may be used in production of solar cells (photo-converters) Substance of the invention: the device consist of a crucible for a melt mounted inside a heater, a substrates connected to gears of their relocation and a capillary feeding mechanism. The substrates are made out of a carbonic reticulated fabric, and the capillary feeding mechanism consists of two horizontal sections, located to the left and to the right of the crucible, each of which has a tail swathed by harnesses out of a carbonic thread. The crucible is made with the bottom hollow elongated spout supplied with an independent heater, under the crucible there is a tank for a drain of the crucible residue, the inner surface of which is coated by a layer of a hexagonal boron nitride, and above the crucible a vibrating feeder for feeding the ground silicon is mounted.
EFFECT: the invention ensures growing of polycrystallic layers from a melt of silicon.
FIELD: devices for growing from a melt of polycrystalline layers of silicon used for production of solar sells.
SUBSTANCE: the invention is pertaining to the field of growing from a melt of polycrystalline layers of silicon and may find application in production of solar cells (photoconverters). The substance of the invention: the device includes a crucible for a melt, a heater, a substrate linked with the gear of its relocation and a capillary feeding mechanism. The substrate is made out of a carbon reticular fabric, the heater consists of two sections of heating: a square section, inside which the crucible is mounted, and a right-angled section located above the substrate. At that the cross-section of the heater components is selected so, that the section of heating of the crucible is overheated in respect to the section of heating of the substrate. For a capillary feeding of the melt of silicon from the crucible use harnesses made out of a carbon filament spooled on a tail-end of the feeding mechanism. For replenishment of the level of the melt in the crucible use a vibrofeeder to feed the crushed silicon. The technical result of the invention is an increased productivity of the device and formation of conditions for production of the orientated coarse-crystalline structure of a silicon layer on the substrate naturally open for making of the rear electrical contact.
EFFECT: the invention ensures an increased productivity of the device, production of the orientated coarse-crystalline structures of the silicon layers on the substrates.
1 dwg 1 o
FIELD: chemical industry; methods of production of the semiconductive materials.
SUBSTANCE: the invention is pertaining to chemical industry, in particular, to the method of production of the single-crystal silicon and may be used at growing the single-crystal silicon by Czochralski method. The method provides for smelting-down of the source silicon in the crucible, injection of the crystalline seed, the crystal drawing out from the melt in the rotating crucible onto the rotating seed at the coincidence of the direction of rotations of the crucible and the crystal. At that in compliance with the growth of the crystal in process of its production the speed of rotation of the crucible and the speed of rotation of the crystal is a step-by-step increasing at keeping approximately constant the ratio of the speeds of rotation of the crucible and the crystal. The method ensures production of silicon monocrystals with the homogeneous radial distribution of the dopant impurity and oxygen and with the uniform distribution of the required amount of oxygen along the length of the crystal.
EFFECT: the invention ensures production of silicon monocrystals with the homogeneous radial distribution of the dopant impurity and oxygen and with the uniform distribution of the required amount of oxygen along the length of the crystal.
6 cl, 2 ex, 2 dwg
FIELD: production of semiconductor material monocrystals.
SUBSTANCE: method involves formation of barium-containing coating of barium hydroxide on inner and/or outer surface of heated quartz crucible, said coating being formed by spraying suspension of barium hydroxide in air atmosphere on surface of quartz crucible heated to temperature of 100-150 C.
EFFECT: improved uniformity and homogeneity of coating to thereby increase yield of product and reduce discard in production of monocrystalline silicon ingots.
FIELD: treatment of silicon mono-crystals grown by Czochralski method, possibly manufacture of mono-crystalline silicon chips- members of solar batteries and integrated circuits.
SUBSTANCE: method comprises steps of pseudo-squaring of silicon mono-crystal for further grinding ribs of pseudo-squared ingot; cutting mono-crystals by chips. Ribs are ground alternatively; each rib is ground layer by layer in motion direction of tool and in parallel relative to lengthwise axis of ingot.
EFFECT: improved quality of mono-crystalline silicon chips due to safety of near-contour region of worked zone of ingot, lowered material (silicon) losses at working ingots.
3 cl, 1 ex, 1 tbl, 3 dwg
FIELD: chemistry; profiled silicon monocrystals manufacturing.
SUBSTANCE: silicon monocrystals are produced by crucible-free vertical float-zone method, which implies induction generation of a melt drip on initial vertical silicon ingot, seeding of monocrystal being grown on a seed  oriented silicon monocrystal, building-up of crystal conical portion to specified diameter, while moving initial ingot and coil in horizontal plane, under conditions, which provide for convex crystallisation front, and emergence of face (111) at melt centre surface at the moment the monocrystal specified diameter is reached. This is followed by hollow monocrystal growing, melt column, which connects the melt ring resting on the growing monocrystal with the drip on initial ingot, being positioned between edge of (111) face and cylindrical surface of the growing monocrystal.
EFFECT: production of silicon hollow (tubular) dislocation-free high-purity perfectly structured monocrystals with  orientation.
FIELD: technological process.
SUBSTANCE: invention pertains to growth of monocrystalline silicon layers from a molten mass, and can be used in making solar cells (photoconverters). The device consists of a crucible for melting, a heater, consisting of two heating sections: a square one, the inside of which is fitted with a crucible, and a rectangular one, put over a substrate, a substrate, linked to its displacement mechanism, capillary feeder, bundles of carbon fibres, wound on the tail of the feeder, and a vibrating feeder for supplying crushed silicon. The substrate used is a carbon foil, covered by pyrographite layers. The capillary feeder has an opening for putting in the substrate, and the rectangular heating section is symmetrical about the substrate and has vertical incisions for letting in the substrate.
EFFECT: increased output of the device due to growth of thin silicon layers at the same time on both surfaces of the substrate, due to reduction of the specific consumption of initial silicon due to that, the substrate does not get soaked in the molten mass.
1 ex, 2 dwg
FIELD: technological processes.
SUBSTANCE: method of production of regular systems of nano-size silicon whiskers includes preparation of silicon plate by masking of its surface with photoresist, making holes in it, electrochemical deposition of metal islets into photoresist holes from electrolyte solution, and installation of prepared plate into growth furnace with further growing of silicon whiskers on it, at that cylindrical openings in photoresist are created with diameter of less than 250 nm by means of imprint-lithography, metal islets are deposited with thickness of less than 12.5 nm, after that photoresist is removed in 5% solution of hydrofluoric acid.
EFFECT: method makes it possible to considerably facilitate creation of nano-technological instruments on nano-crystals.
FIELD: metallurgy, crystals.
SUBSTANCE: invention concerns field of semiconducting materials metallurgy and can be used mainly at receiving of substances crystals with fusion temperature, increasing quartz softening temperature, for instance at growing of single-crystal silicon by means of Czochralski growth technique. Method includes location of quartz crucible in compound support, formed by cylinder course and disk, feed stock charging into quartz crucible, mounting of crucible with support into furnace, charging melting, single-crystal seed introduction and single crystal withdrawal from the melt. In particular technique cylinder course is implemented in the form of glass, bottom of which is formed by means of location at support disk layer of the same material, from which it is made cylinder part of course, crucible is located in course with ability of sliding, crucible is installed into furnace in a way that crucible bottom is in area of maximal heating. Melting mode is specified, providing reliable softening of spherical bottom-most part of quartz crucible, crucible is held till melting of charging material, then it is pulled down inside of furnace in position of growing process start and there is fixed single crystal growing mode.
EFFECT: decreasing of cost price of single-crystal silicon at the expense of crucible durability increasing and ability of it multiple additional charging by initial raw materials.
4 cl, 3 dwg
FIELD: neutron transmutation doping of industrially produced silicon in fast reactors.
SUBSTANCE: proposed device primarily designed for type RBMK reactors has through flow path with bellows compensator and external shell fixed to the latter and made in the form of sleeve, build-up path, and head, all joined in tandem; sleeve is mounted through its top part on supporting shoulder of through flow path in bore of graphite blocks of neutron reflector; device is also provided with internal tube mounted in a spaced relation inside external shell, as well as with cooling liquid inlet and outlet units forming cooling system together with external shell and internal tube; ionizing radiation shielding means are installed inside and outside of external shell; device is also provided with telescopic hanger of irradiation container disposed within internal tube and joined to bottom section of hanger; the latter is provided with vertical displacement and rotation actuator disposed in upper part of external shell; sleeve condition checkup system is placed outside of external shell.
EFFECT: improved properties of doped silicon, enhanced doping uniformity, reduced trouble probability.
4 cl, 7 dwg
FIELD: metallurgy, crystal growing.
SUBSTANCE: invention refers to process of production of AIIIBV semi-conducting compositions. Mono-crystals of indium antimonide alloyed with tin are produced by means of bombardment with a full specter of reactor neutrons with successive heating, annealing and cooling. Heating is carried out at the rate of 20÷40 deg/min to temperature of annealing, defined by the formula Tanneal=450+(tgNsn-14)-7 [°C], where Nsn is concentration of introduced alloying addition of tin [cm-3]; annealing is performed during 20 minutes, while the successive cooling is carried out at the rate of 5-10 deg/min to the temperature of 350÷400°C, and further at the rate of 20-40 deg/min to an ambient temperature.
EFFECT: alloying of indium antimonide plates with tin to high concentrations, also upgraded uniformity of tin distribution and electrone mobility.
2 ex, 1 tbl
SUBSTANCE: method for neutron doping of a substance involves slowing down fast source neutrons with a retarder substance, forming a stream of slow neutrons in a selected region and irradiating the substance to be doped with the slow neutrons. During the slowing down process, the fast source neutrons are separated according to propagation angles thereof; streams thereof moving a direction selected by the structure of the retarder substance are selected; streams selected by the structure are summed up, formed into a narrow band and directed onto the substance to be doped, which is controllably moved in the focal region of the neutron streams.
EFFECT: high efficiency of the doping process and forming regions with high degree of doping in given areas of the doped substance.
5 cl, 3 dwg, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to production of alloys diamonds to be used in electronics and instrument making s well as jewellery stones. Alloyed diamond is produced by chemical deposition of gas phase on substrate in reaction chamber 2. Alloying solid-state component 7 is placed in alloying chamber 3. The latter has at least three connection flanges. Two of them are designed to connect alloying chamber 3 with working gas feed line 1 while third flange allows passage of pulsed laser radiation 8 via translucent window 5 into alloying chamber 3 for sputter of alloying component 7. Note here that alloying component concentration in diamond is adjusted by varying the laser parameters: laser diode pump current, laser pulse frequency and distance from laser radiation focus to alloying component surface. Working gas can be composed of the mix of hydrogen and methane at the ratio of 98:2% to 90:10%. Additionally, oxygen can be added thereto.
EFFECT: precise alloying in the wide range of concentrations (1014 atom/cm3 to 9×1019 atom/cm3) of boron, sulphur and silicon.
3 cl, 1 dwg, 4 tbl, 4 ex