RU2032960C1 - Process of manufacture of epitaxial structure containing layers of indium phosphide and arsenide-indium phosphide in as oox p oo1-oox - Google Patents

Abstract

FIELD: manufacture of semiconductors. SUBSTANCE: process allows technology of growth of structures with "stop-layers" to be simplified. Prior to growth of working structure flux of arsenic trichloride with mole share 1,9·10^-3-5,3·10^-3 is additionally injected into steam-gas mixture and "stop-layer" is grown in the course of 4-10 min. EFFECT: facilitated manufacture. 2 dwg, 1 tbl

Description

 The invention relates to a technology for producing semiconductor structures used in the manufacture of semiconductor microwave devices, in particular Gunn diodes, field effect transistors, mixing diodes.

 For many types of semiconductor devices, it is necessary to obtain structures that would allow selective etching. In particular, in some instructions of microwave devices it is required to completely remove the substrate, without affecting the working structure, or to produce a crystal, the working structure of which is located strictly on the substrate. In a number of variants, such problems are solved using heterostructures, for example, those where a material is used as a substrate, which differs in its chemical properties from the material of the working structure. In addition, layers of solid solutions, in particular in combination with layers of other materials, may be of independent interest as layers that are included in the working structure of the device, for example: a diode of a current-controlled negative resistance, a heterobipolar transistor.

= 500. За счет слоя твердого раствора InAs_xP_1-х снижалась дефектность в эпитаксиальном слое InP. Данный способ наращивания имеет ряд недостатков.A known method of growing InP on Si in OMVPE, allowing you to change the defectiveness of InP through the use of InAs _x P _1-x / InP superlattices [1]
A horizontal reactor was used to grow the structures. As starting materials in this method, trimethyl indium, tetraethyl gallium, 10% AsH ₃ in H ₂ and 100% PH _{3 are used} . With the growth of InAs _x P _1-x (x 0.3) solid solution, the ratio of gas flows

= 500. Due to the InAs _x P _1-x solid solution layer _{, the} defectiveness in the InP epitaxial layer decreased. This method of building has several disadvantages.

= 500.The use of organometallic compounds and hybrids, which are strongly toxic poisonous substances, require special safety conditions and, as a result, complicates the technology. In addition, an accurate dosage of the arsine stream introduced into the reactor in small quantities is required. The need for an accurate dosage of arsine is due to the large ratio of gas flows

= 500.

The closest technical solution to the invention is a method of growing InAs _x P ₁ epitaxial layers on YaAs, InP and InAs substrates using InAs AsCl ₃ InP PCl ₃ H ₂ , InAs HCl InP HCl H ₂ and In AsCl ₃ In PCl ₃ H ₂ gas phase systems [2]
To build up the InAs _x P _1-x epitaxial layer, we used a reaction chamber divided into 2 parts in the source zone, InAs part, and InP source part. Source reactions in both parts were performed independently. Source temperature was 800 ^C, the substrate temperature was varied from 650 to 800 ° ^C. The source-side relationship InAs hydrogen stream to flow from the source InP equal to 2 and the total flow varied from 150 to 600 cm ³ / min.

 A significant disadvantage of this method is that the buildup of such structures by gas transport chloride epitaxy is difficult, since the epitaxy process in this case is complex, requires a significant complication of the design of the reaction chamber, gas circuit, as well as the use of several sources.

 The aim of the invention is to simplify the technology of growing epitaxial structures containing layers of indium phosphide and indium arsenide-phosphide.

This goal is achieved by the fact that upon sequential deposition of layers of InAs _x P ₁ and indium phosphide from the gas phase obtained by passing a gas mixture of phosphorus trichloride and hydrogen over an indium source, an additional arsenic trichloride stream with a molar fraction of 1.9˙10 ^-3 ÷ 5.3 -10 ^-3 in the gas mixture, and under the source of indium a stream of the gas mixture with a molar fraction of phosphorus trichloride equal to 2.2 2,210 ^{-3 is} allowed for 4-10 minutes and then stop the flow of additional flow. As a result of the interaction of InP with As on the surface of the substrate (or epitaxial layer), an InAs _x P _1-x solid solution layer grows (0 ≅X≅ 0.16). The upper limit of the AsCl ₃ flux is limited by the fact that, with a small fraction of AsCl ₃ more than 5.3˙10 ^-3 , an excess of HCl is formed, which transfers the process of growing the InAs _x P _{1 x} epitaxial layer to the etching stage of the substrate (epitaxial layer). The lower limit of the AsCl ₃ flux is limited by the arsenic content in the InAs _x P _1-x layer, since an InP layer is formed with a molar fraction of AsCl ₃ supplied to the growth zone 0. The InAs _x P _1-x layer is expanded over 4-10 minutes. In this case, the thickness of the stacked layer is 0.05-0.2 microns. The upper limit of the thickness is limited by the fact that, with a thickness of more than 0.2 μm, the InP working layer will have a high dislocation density, which leads to a deterioration in the quality of the structure.

 The lower limit is limited by the fact that when its thickness is less than 0.05 μm, the likelihood of its etching increases with selective removal of the substrate (epitaxial layer).

Compared with the prototype, the use of the invention when building epitaxial layers of InAs _x P _1-x solid solution is most simple from the point of view of its implementation, it will simplify the design of the reaction chamber and the gas circuit. The growth was carried out on an installation of epitaxial building type ETR-100.

In FIG. Figure 1 shows the design of the reaction chamber, which is typical for the buildup of layers of compounds A ³ B ⁵ , and schematically shows the directions of gas flows.

The chamber contains a hydrogen injection channel 1, an AsCl ₃ supply channel 2, an etching dilution channel 3, a helium supply channel 4, an etching channel 5, a growth channel 6, an etching dilution channel 7, a reaction chamber 8, an indium source 9, a pedestal 10, a phosphide substrate 11 India.

In the reaction chamber 8 has a source 9 and the pedestal 10 to the substrate 11 of indium phosphide, at 750 and 650 ^C, respectively. A hydrogen stream is passed through channel 1 of 30 l / h; a stream of hydrogen through channel 7 of 7 l / h; helium flow through channel 4 of 37 l / h and the pedestal 10 is heated with substrates 11 of indium phosphide for 25-30 minutes. After the specified time, gas etching of the indium 11 phosphide substrate is carried out for 4-6 minutes, for which a stream of a gas mixture of H ₂ + PCl _{3 is} fed through channel 5 of 10 l / h and through channel 6 of 32 l / h. At the end of the etching time, the flow of the H ₂ + PCl ₃ gas mixture is stopped through channel 5 and an additional H ₂ + AsCl ₃ gas mixture flow of 0.3-3.5 l / h is supplied through the channel 2 to the deposition zone and the InAs layer builds up _x P _1st . The build-up time, the molar fraction of AsCl ₃ and PCl ₃ , the linear velocity of the gas flow above the substrate and the build-up speed are shown in the table.

After the build-up time, InAs _x P _1-x stops the flow of the gas mixture (H ₂ + AsCl ₃ ) through the channel and, if necessary, unload the structure or increase the epitaxial layers of InP.

 In FIG. Figure 2 shows one of the design options of a discrete device, including a Gunn diode and a varicap, in which a given crystal geometry is formed by lithography and selective layer removal methods.

 In FIG. 2, the following designations are used: a semi-insulating substrate 12, epitaxial layers 13 of highly doped indium phosphide, epitaxial layers 14 of selectively removed material, a lightly doped layer of indium phosphide 15, which is the active layer of Gunn diode 15, a lightly doped layer of indium phosphide 16, which is the working layer of a varactor diode, deposited layers 17 gold, transitions 18 Schottky, ohmic contacts 19.

The proposed method allows the formation of layers of InAs _x P _{1 x} with arsenic content (0-16%), which can be used: as a "stop-layer", as intermediate layers that reduce defectiveness in the working layers; for producing InAs _x P _1-x / InP superlattices, etc. In addition, when using the invention due to its simplicity and sufficiently high accuracy of controlling the suppressed AsCl ₃ flow, the reproducibility of the process increases, and therefore, the percentage of yield of suitable structures increases. The economic effect in this case can be obtained by increasing the percentage of yield of epitaxial structures suitable for the manufacture of microwave devices.

Claims (1)

Process for the preparation of epitaxial structures comprising layers of indium phosphide and gallium-indium phosphide IN As _x P _1-x, comprising substrate heating, gas etching in a mixture of phosphorus trichloride, helium, and hydrogen, sequential deposition of layers of In As _x P _{1 - x} and indium phosphide from the gas phase obtained by passing a stream of a gas mixture of phosphorus trichloride and hydrogen over an indium source, characterized in that, in order to simplify the technology for producing structures, an additional mouse trichloride stream is supplied when an indium arsenide-phosphide layer is deposited with a molar fraction of 1.9 · 10 ^{- 3} 5.3 · 10 ^{- 3} in the gas mixture, and a stream of the gas mixture with a molar fraction of phosphorus trichloride equal to 2.2 · 10 ^{- 3 is} passed over the source of indium for 4 10 minutes and then stop the flow of additional flow.

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