CS213947B1 - Method of manufacturing hetero-junctions - Google Patents

Abstract

A method for producing heterogeneous transitions which is different for one to three gases chemical composition containing chalcogenic elements, glow discharge at a pressure of 10 to 9 to 300 Pa for 30 hours seconds to 24 hours, and after layer formation heteropoints and after removal of the reaction of the inert gas stream repeats one to four times.

Description

(54) Method for the production of heterodipers

Process for the production of heterotransitions, wherein one to three gases of different chemical composition containing chalcogenic elements are subjected to a glow discharge at a pressure of 10 to ⁹ to 300 Pa for 30 seconds to 24 hours, and after the formation of the heterotransition layer and gas, the process is repeated one to four times.

The present invention relates to a process for the production of heterodipers. In this context, a heterotransition is a structure composed of two semiconductor layers having different physical properties.

Chalcogenic semiconductors, i.e., non-crystalline semiconductors containing chalcogenic sulfur elements, selenium, are usually prepared from a grating starting material, and the melt is quenched to form a non-crystalline, glassy material. The semiconducting material prepared in this way is then used to prepare layers for heterotransitions in various ways.

A method for producing heterogeneous e-chalcogenic semiconductors in which the layers are obtained by thermal vaporization is known in the art. Iren Dam and L. Stourač (Czech.J.Phye. B27 (1977) 613) used this procedure for the production of heterotransitions. In this process, a chalcogenic semiconductor is first prepared from the melt and in a vacuum, resistively heated apparatus, and allowed to evaporate and settle on prepared substrates remote from the heating site. However, to prepare each of the other layers, the vacuum apparatus can be opened, the starting material changed, resealed and evacuated.

The disadvantage of this method of production of heteroconversion is the necessity of multiple rotations. the vortexing and closing of the vacuum system and the necessity of using very complex and economically expensive devices. The starting material for the vaporization must in particular also be prepared from the melt. Another defect is the high working temperature close to the glass transformation temperature, resulting in numerous defects in the prepared layer of chalcogenic semiconductors; also due to their existence, Fermi's energy in the semiconductor and the insensitivity to both the admixture content and the physical properties of heterotransitions are very limited, which greatly limits the use of these materials for electronic purposes (H.Fritzache; International Conference on Amorphous and Liquid Semiconductors, Edinburgh, 1977) )). Another disadvantage is the unequal layer composition caused by different evaporation rates of the individual components of the chalcogenic semiconductor.

Another known method for the preparation of heterotransitions is the reactive sputtering of thin films (R. Flaak et al., Proc. Con. Amph. And Liquid Semiconductore, Edinburgh (1977); University of Edinburgh, 524; RCFrey et al. J.Appl .Phys. 7 (1979) 4866). A method of sputtering is known from the monograph Physical Vapor Deposition, Airco Inc, (1976) USA et al.

For sputtering, it is also necessary to first prepare a chalcogenic semiconductor from the target melt. Prior to sputtering, a sputtering target of the desired composition is first placed in a vacuum apparatus and sprayed under reduced pressure to form a desired layer on the prepared substrates. To prepare a longer layer, however, it is necessary to replace the target, evacuate the work area again and apply another layer.

213947 ....... ' ² '

The described process for the production of heterologous transitions by schalkogenic semiconductors has some advantages, such as the need to change the sputtering targets and cancel the vacuum between the deposition of the individual layers of heterologous transitions. In the course of the described procedure, islets also plucked from the target and formed an unequal structure that is inhomogeneous. There are also differences in the composition of one layer. The same drawback as in the previous methods is the requirement that the corresponding chalcogenic melt halide be prepared prior to the actual work.

It is also known to prepare some materials such as gaseous semiconductors in a glow discharge. Thus, amorphous silicon layers were obtained by decomposing the silane SiH 2 (HFSterling and RCGSwann: Solid State Electronics 8 (1965) 653; M. Tanielien, M. Chatani, H. Fritzsch, V. Smid, PD Pearsons. Proc. Int. Amorphous and Liquid Semiconductors, Cambridge, USA (1979) It is also known to prepare amorphous germanium by decomposing GeH 2 (RC Chittick: Non Crystal.Solids 3 (1970) 255) and phosphorus and nitrogen compounds (S. Vepek et al. To date, however, the preparation of heterogeneous transitions with chalcogenic elements in a glow discharge has not been known, nor has the possibility of preparing thin-film structures with chalcogenic semiconductors been considered.

The disadvantages of vapor deposition and sputtering are eliminated by this method of heterofunction production. SUMMARY OF THE INVENTION The present invention provides a process in which, in a confined space at a pressure of 10 to 300 Pa, a gas or a mixture of two to three gases of different chemical compositions is characterized, one gas being characterized by the general formula XY _n , , nitrogen, gallium, germanium, aluminum, silicon, selenium, sulfur, tellurium, carbon or a radical of formula ZWm wherein Z is arsenic, germanium, silicon, selenium, sulfur, tellurium or carbon, and W represents a halogen, hydrogen or hydrogen-containing radical , carbon optionally also nitrogen and / or oxygen, further wherein Y is halogen, hydrogen or a hydrogen-containing radical, carbon optionally also nitrogen and / or oxygen, and n and n are natural numbers of 2 to 4, which may be the same or may be different from one another, the second gas having a composition corresponding to the general formula XY _n , wherein the aymols X, Y and _n are as defined above, or is argon or hydrogen, and the third p the lanne is argon, nitrogen or oxygen or hydrogen, at a pressure in the range of 10 to 300 Pa for 30 seconds to 24 hours with a glow discharge preferably at a frequency of 13.56 MHz, and then removes undesirable and reaction residues in an inert gas stream; alternatively, the process is repeated one to four times. The ratio of the two starting gaseous components involved in the reaction is stable or variable in the range of 10 ^-4 to 99.9999: 99.9999 to 10 ^-4 % by weight during the glow discharge and / or heterogeneous layer growth.

The process according to the invention allows the use of one or a mixture of multiple gases containing a chalcogenic element for the preparation of one or more layers of a thin-film structure. Preferably, the ratio can be varied during the glow discharge

% Of the reactants of the gas mixture in the range of 10 to 99.9999 wt. % of one gas to 99.9999 to 10 " of the second gas, so that when the vacuum is canceled or restored, the work does not have to be interrupted, as is the case with the known methods ·

The advantage of this method of manufacture is that the layers can be applied at a relatively low temperature, generally lower than the glass transformation temperature, so that defects typical of glassy semiconductors are avoided while improving the quality of the layers. The production of heterogeneous transitions is without difficulty, without the need to cancel the vacuum and renew it again by applying individual layers; this also avoids the reaction of the surface of the layer of heterotransitions with the surrounding atmosphere, which could occur after the deposition, the first return and before the second layer is applied; this will also result in improved electrical properties of the heterogeneous transitions and improved reproducibility of the final product. Process The process for the production of heterotransitions according to the invention allows the deposited layers to have a homogeneous composition and the ratio of the individual components of the layer to be accurately controllable and reproducible both temporally and spatially. The invention allows for a gradual heterotransition even between substances containing the same chemical elements, which until now has not been achieved by any of the known manufacturing processes such as vapor deposition and sputtering. According to the invention, heterotransitions with controlled composition in the individual layers of the final product can also be prepared. Another advantage is that the equipment required for manufacture is structurally simple, and does not require any rotating or moving parts to operate in an environment with considerably reduced atmospheric pressure.

The following examples illustrate the invention without limiting it in any way.

Example 1

A SiH4 silane is introduced into the reaction chamber at a reduced pressure of 10 bar. The gas flow is controlled so that the pressure in the reaction chamber is maintained at 10 Pa. The 13.56 UHz generator is turned on, ignited for 30 seconds, resulting in silane decomposition and reaction between the components in the gas phase and on the walls of the reaction chamber. The surfaces exposed to the glow discharge are covered with a layer of silicon; After three times flushing the reaction space with argon and after reducing the pressure to 10 ^-8 mbar is fed into the mixture germanovodíku and hydrogen sulphide in a ratio of 1: 1 for 5 hours are exposed doutnayého discharge at a pressure of 300 mbar. After flushing the reaction space with nitrogen and evacuating twice, the silicon-germanium heterosubjection pads were removed.

Example 2 * - Q

A gaseous mixture containing 5 wt. % hydrogen germanium, 5 wt. % of C ₂ H ₂ and 90 wt. argon. The gas flow is rectified so that the pressure in the reaction space is 10 Pa, after the discharge has been switched on for 10 hours, the reaction space is purged with a stream of argon and the pressure is reduced to _7.

Fa. A mixture of hydrogen sulphide and nitrogen in a ratio of 80: 20% by weight is then introduced, and the discharge is ignited for 21 hours at 1 Pa. The resulting heterotransition has the composition kgrbid of germanium-sulfur compound and nitrogen.

Example 3

A 9: 1 mixture of silica fluoride and hydrogen was introduced into the reaction chamber at a reduced pressure of 300 Pa, then exposed to a glow discharge for 2 hours, purged the reaction space with nitrogen and evacuated to 10 Pa, then introduced a 1: 4 mixture of hydrogen arsenic and selenium hydrogen at a pressure of 1 Pa ignites a glow discharge for an hour. After flushing the reaction space with a stream of argon, the silicon-compound heterosubstance pads were quenched with arsenic and selenium.

Example 4 '

A 1: 9 mixture of Ge (OC ₂ H 2) and argon was introduced into a 10 Pa closed reactor and exposed to a glow discharge for 8 hours at 10 Pa, followed by a mixture of SiH 2 silane and hydrogen AH. % in the ratio 99.99: 0.1 wt. %, which is diluted with argon in an argon to mixture ratio of 9: 1 wt. %. The pressure in the reaction space is maintained at 100 Pa, after which a glow discharge is switched on for 1 hour and the ratio of silane to hydrogen arsenic is adjusted so as to reach 50% by mass during the course of the layer growth. % silane to 50 wt. of arsenic hydrogen. This creates a second silicon-arsenic-based germanium-semiconductor heterodalent layer, wherein the arsenic concentration increases in the direction from the heterodalent to the surface of the second deposited layer.

Example 5

A mixture of Ga (CH 2) 4 and a ratio of 50:50 wt. and exposed to a glow discharge for 2 hours at a pressure of 100 Pa. To this reaction space purged with argon and evacuated to a pressure of 10 ^- ^ Pa, whereupon the mixture is brought arsenic and argon in a ratio of 10:90 wt%. and subjected to a glow discharge for 2 hours at a pressure of 10 Pa. After purging the reaction space with argon, the pads and the formed heterotransfer gallium arsenic are removed.

Example 6

A mixture of silane and diborane in a ratio of 99.9% by weight is introduced into a closed reaction chamber at a pressure of 10 bar. silane; 0.1 wt. diborane and then subjected to a glow discharge for 10 minutes at 5 Pa. The procedure is the same as in Examples 1 and 3.

This yields a complex thin film structure consisting of five layers: silicon-boron / silicon / germanium sulphide / silicon / arsenic selenium compound.

Claims (2)

SUBJECT OF THE INVENTION CLAIMS 1. A method for producing heterogeneous transitions between two or more layers, with a thickness in the range 0.15 to 100 microns, wherein at least one element comprises a chalcogenide, characterized in that _q enclosed space at a pressure between 10 Pa ^7-300 on the starting material consisting of one to three gases differing chemical compositions, of which one the gas is characterized by the general formula XY _n , wherein X denotes arsenic, nitrogen, gallium, germanium, aluminum, silicon, selenium, sulfur, tellurium, carbon or a radical of the formula ZW _ffi in which Z denotes arsenic, germanium, silicon, selenium, sulfur, tellurium, And W represents halogen, hydrogen or a radical containing hydrogen, carbon optionally also nitrogen and / or oxygen, further wherein X represents halogen, hydrogen or a radical containing hydrogen, carbon optionally also nitrogen and / or oxygen, and the symbols nam are natural numbers 2 to 4, which may be the same or different from each other, the second gas having a composition corresponding to the general formula XX _n , where symboly, ϊ and _n are as above or is argon or hydrogen, and the third gas is argon, nitrogen, or oxygen or hydrogen, at a pressure in the range of 10 to 300 Pa for 30 seconds to 24 hours with a glow discharge, preferably corresponding to a frequency of 13.56 MHz, whereupon the reaction residues are removed by a stream of inert gas and optionally repeat the procedure one to four times. 2. A process for the production of hetero-transitions according to claim 1, characterized in that the ratio of the two gaseous reactants involved in the reaction is stable or adjustable during the glow discharge and / or heterogeneous layer growth between 10 and ⁴ to 99.9999 : 99.9999 - 10 ^4% by weight.