GB2234529A - Epitaxial growth process - Google Patents

Epitaxial growth process Download PDF

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Publication number
GB2234529A
GB2234529A GB8917097A GB8917097A GB2234529A GB 2234529 A GB2234529 A GB 2234529A GB 8917097 A GB8917097 A GB 8917097A GB 8917097 A GB8917097 A GB 8917097A GB 2234529 A GB2234529 A GB 2234529A
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Prior art keywords
substrate
epitaxial layer
atmosphere
semiconductor
compound semiconductor
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GB8917097A
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GB8917097D0 (en
GB2234529B (en
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Stephen Rolt
Kenneth George Snowden
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STC PLC
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STC PLC
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
    • H01L21/02455—Group 13/15 materials
    • H01L21/02461—Phosphides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/04—Coating on selected surface areas, e.g. using masks
    • C23C16/047—Coating on selected surface areas, e.g. using masks using irradiation by energy or particles
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/301—AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/10—Heating of the reaction chamber or the substrate
    • C30B25/105—Heating of the reaction chamber or the substrate by irradiation or electric discharge
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/40—AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • C30B29/42—Gallium arsenide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02373—Group 14 semiconducting materials
    • H01L21/02381—Silicon, silicon germanium, germanium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02538—Group 13/15 materials
    • H01L21/02543—Phosphides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02538—Group 13/15 materials
    • H01L21/02546—Arsenides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02636—Selective deposition, e.g. simultaneous growth of mono- and non-monocrystalline semiconductor materials

Abstract

An epitaxial layer of a compound semiconductor is grown in selected regions of a substrate by a laser activation process wherein the substrate is heated to 300 to 350 DEG C in an atmosphere of hydrides and low alkyls of the semiconductor elements and is irradiated by focussed ultraviolet laser radiation to effect deposition of the semiconductor. Typically the atmosphere comprises a mixture of arsine and trimethyl gallium to effect deposition of gallium arsenide. The process may be used in the fabrication of multilayer structures and quantum well devices.

Description

EPITAXIAL GROWTH PROCESS This invention relates to a process for the epitaxial growth of compound semiconductor material on a semiconductor substrate.
A particular problem in the production of devices for compound semiconductor material, such as gallium arsenide (Ga As) is the necessity to provide an epitaxial layer of the compound material on a single crystal substrate body. Currently available compound semiconductor material is in general of insufficient quality for the fabrication of devices directly therein. For this reason, manufacturers of compound semiconductor devices generally provide a high quality epitaxial layer in which the devices are then formed.
Epitaxial growth is also required in the fabrication of multilayer structures such as semiconductor lasers and quantum well devices.
Structures of this nature require the provision of layers of different materials, e.g. GaAs and GaAlAs, each layer being crystal matched to the overall structure.
Currently developed epitaxial growth processes provide an epitaxial layer over the entire substrate surface, i.e. these processes are non-selective.
However, a number of devices have recently been proposed in which epitaxial material is required only in selected portions of the substrate. Using conventional techniques devices of this nature require either a mask to confine epitaxial deposition to the required areas, or a selective etching stage which again requires the provision of a mask. Such processes are time consuming and Can lead to a reduction in yield of functional devices.
In an attempt to overcome this problem, processes have been developed in which high temperature, typically 450 C, epitaxial growth is achieved by optical wavelength laser assisted thermal decomposition of arsenic and gallium containing organic compounds.
The high temperatures required for such processes have been found to result in thermal degradation effects such as dopant redistribution.
The object of the invention is to minimise or to overcome these disadvantages.
According to the invention there is provided a process for forming selectively an epitaxial layer of a compound semiconductor on a single crystal semiconductor substrate, the process including exposing the substrate to an atmosphere of hydrides and/or alkyls of the elements of the compound semiconductor and irradiating selected regions of the substrate with an ultraviolet laser whereby to effect growth of epitaxial compound material on said selected regions.
According to the invention there is further provided a process for forming selectively an epitaxial layer of gallium arsenide on a single crystal semiconductor substrate surface, the process including exposing the substrate at a temperature of 300 to 350 0C and under reduced pressure to an atmosphere comprising a mixture of arsine (AsH3) and trimethyl gallium (Ga(CH3)3) diluted with hydrogen, and irradiating selected regions of the substrate with inherent ultraviolet radiation having a wavelength of 190 to 250nm and an energy density of 8 to 12mJcm'2 whereby to effect selective epitaxial growth of gallium arsenide on the irradiated regions of the substrate surface.
As deposition is effected only on those regions of the substrate irradiated by the laser, a patterned deposit is obtained without the need for an in-contact mask. Further, by restricting the substrate temperature 0 to 350 C, the previously experienced problems of dopant redistribution and surface distortion are substantially eliminated.
An embodiment of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a part-schematic diagram of an apparatus for laser induced epitaxial growth of semiconductor material, and Figs. 2 and 3 are respectively plan and sectional views of a deposition cell for use in the apparatus of Fig. 1.
Referring to the drawings, a single crystal semiconductor substrate body 11 to whose surface an epitaxial layer is to be applied, is placed in a deposition cell or chamber 12 in thermal contact with a heater 13. The body 11 is exposed to a vapour containing hydride of the constituent elements of the semiconductor compound. Typically we effect epitaxial growth of gallium arsenide and for this purpose a mixture of arsine (As H3) and trimethyl gallium (Ga (CH3)3) is employed. These reactant vapours are mixed with a reducing carrier gas, preferably hydrogen.
The gas and vapours are supplied to the cell 12 from mass flow controller 14 via a gas manifold 15 and a throttling valve 16. The cell 12 is evacuated via pump 17 thereby drawing the reactants via the throttling valve 16 across the surface of the substrate 11.
Typically the gas pressure within the cell is 25 to 100m torr (3.3 to 13.3 newtons m Preferably the major proportion of the gas mixture comprises the carrier gas. In a typical deposition process we employ a mixture containing 1 volume % arsine and 0.5 volume % trimethyl gallium, the remainder being hydrogen. Advantageously the gas mixture comprises 95 to 99 volume % hydrogen.
Epitaxial deposition of compound semiconductor on to the substrate surface is effected by irradiation of selected regions of the substrate 11 by ultraviolet radiation from a laser 18. The laser output beam is steered by quartz prism 19 and is focussed on to the substrate surface by quartz lens 20. Typically the laser 18 is a krypton flouride excimer laser operating at a wavelength of 248 nm. The energy density of the laser beam at the substrate surface is preferably 8 to -2 12 m J cm . We have found that energy densities above about 15 m J cm 2 result in poor quality growth and therefore, higher energy densities should be avoided.Advantageously, the laser wavelength is within the range 190 to 250nm In use, the substrate body 11 is heated to a temperature of about 3500C via the heater 13 and the laser beam is directed at selected regions of the substrate surface to effect epitaxial deposition on those regions. By projecting the patterned laser beam on to the substrate surface, a correspondingly patterned epitaxial growth is obtained without the necessity for an in-contact mask.
Figs. 2 and 3 show the detail of the deposition cell 12. As can be seen, the cell is divided into two portions by a longitudinal partition member 31 (Fig.2) having an opening 32 in register with a window 33 whereby laser light is directed across the cell on to the substrate 11. The portion of the cell contacting the substrate is supplied with reactant materials whilst the other portion is supplied only with the diluent gas, e.g. hydrogen. This arrangement ensures that reactant materials are not in contact with the window 33 thus overcoming the problem of window fouling inherent in many conventional deposition processes.
Advantageously the portion of the cell 12 containing the substrate 11 and heater 13 has a stepped surface profile defining a shoulder 34 against which the substrate abutting with its surface flush with the upstream surface of the cell. This provides substantially laminar flow of reactants across the substrate thus ensuring uniformity of deposition.
The process may also be employed for the epitaxial deposition of ternary or quaternary semiconductor compounds, e.g. GaAlAs or GaInAlAs. These materials are formed in the same way as the binary compounds described above by the addition to the gas mixture of appropriate volatile compounds such as trimethyl indium and tri-isobutyl aluminium.
The process described above is of particular application in the fabrication of multilayer structures such as quantum well devices. Such devices include an active region consisting of a large number, typically 100, of layers of alternate semiconductor composition.
A typical quantum well structure may comprise a repeated layer structure of InP, InGaAs and InAlAs disposed between upper and lower InP layers. Such a structure is described in our copending application No. 89 10993.8 (P.D. Greene 14).
In a further development of the deposition process, the growth of the layers of a quantum well structure may be locally enhanced to provide layers of non-uniform thickness. In this way it is possible to incorporate multiwavelength devices on a single substrate chip.
Whilst the deposition process has been described above with particular reference to opto-electronic devices, it will be appreciated that it is not limited to this application but is of general application to the semiconductor field.

Claims (9)

1. A process for forming selectively an epitaxial layer of a compound semiconductor on a single crystal semiconductor substrate surface, the process including exposing the substrate to an atmosphere of hydrides and/or alkyls of the elements of the compound semiconductor and irradiating selected regions of the substrate with an ultraviolet laser whereby to effect growth of epitaxial compound material on said selected regions.
2. A process as claimed in claim 1 wherein the compound semiconductor is gallium arsenide.
3. A process as claimed in claim 2 wherein said atmosphere comprises a mixture of trimethyl gallium and arsine.
4. A process as claimed in claim 2 or 3, wherein said atmosphere further includes hydrogen.
5. A process as claimed in any one of claims 1 to 4, wherein the epitaxial layer comprises part of a multilayer structure.
6. A quantum well device formed by a process as claimed in claim 5.
7. A process for forming selectively an epitaxial layer of gallium arsenide on a single crystal semiconductor substrate surface, the process including exposing the substrate at a temperature of 300 to 350 0C and under reduced pressure to an atmosphere comprising a mixture of arsine (AsH3) and trimethyl gallium (Ga(CH3)3) diluted with hydrogen, and irradiating selected regions of the substrate with inherent ultraviolet radiation having a wavelength of 190 to 250nm and an energy density of 8 to 12mJcm 2 whereby to effect selective epitaxial growth of gallium arsenide on the irradiated regions of the substrate surface.
8. A process for forming an epitaxial layer of a compound semiconductor on a substrate, which process is substantially as described herein with reference to and as shown in the accompanying drawings.
9. A semiconductor device incorporating an epitaxial layer prepared by the process of any one of claims 1 to 4 or 7.
GB8917097A 1989-07-26 1989-07-26 Epitaxial growth process Expired - Fee Related GB2234529B (en)

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GB2234529A true GB2234529A (en) 1991-02-06
GB2234529B GB2234529B (en) 1993-06-02

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1119968A (en) * 1964-11-06 1968-07-17 Siemens Ag Improvements in or relating to methods producing semiconductor material
GB1228920A (en) * 1967-05-31 1971-04-21
GB2119278A (en) * 1982-04-13 1983-11-16 Michael Paul Neary Improvements in or relating to a chemical method
EP0125318A1 (en) * 1982-11-15 1984-11-21 MITSUI TOATSU CHEMICALS, Inc. Method of forming amorphous silicon film
US4505949A (en) * 1984-04-25 1985-03-19 Texas Instruments Incorporated Thin film deposition using plasma-generated source gas
GB2162369A (en) * 1984-07-26 1986-01-29 Nishizawa Junichi Apparatus for forming semiconductor crystal
GB2163000A (en) * 1984-07-26 1986-02-12 Japan Res Dev Corp Apparatus for forming crystal of semiconductor
GB2163181A (en) * 1984-07-16 1986-02-19 Japan Res Dev Corp Method of manufacturing GaAs single crystals
US4645687A (en) * 1983-11-10 1987-02-24 At&T Laboratories Deposition of III-V semiconductor materials
EP0229633A2 (en) * 1986-01-08 1987-07-22 Gregory A. Roche Apparatus and method for laser-induced chemical vapor deposition
GB2200138A (en) * 1984-07-26 1988-07-27 Japan Res Dev Corp Semiconductor crystal growth apparatus

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1119968A (en) * 1964-11-06 1968-07-17 Siemens Ag Improvements in or relating to methods producing semiconductor material
GB1228920A (en) * 1967-05-31 1971-04-21
GB2119278A (en) * 1982-04-13 1983-11-16 Michael Paul Neary Improvements in or relating to a chemical method
EP0125318A1 (en) * 1982-11-15 1984-11-21 MITSUI TOATSU CHEMICALS, Inc. Method of forming amorphous silicon film
US4645687A (en) * 1983-11-10 1987-02-24 At&T Laboratories Deposition of III-V semiconductor materials
US4505949A (en) * 1984-04-25 1985-03-19 Texas Instruments Incorporated Thin film deposition using plasma-generated source gas
GB2163181A (en) * 1984-07-16 1986-02-19 Japan Res Dev Corp Method of manufacturing GaAs single crystals
GB2162369A (en) * 1984-07-26 1986-01-29 Nishizawa Junichi Apparatus for forming semiconductor crystal
GB2163000A (en) * 1984-07-26 1986-02-12 Japan Res Dev Corp Apparatus for forming crystal of semiconductor
GB2200138A (en) * 1984-07-26 1988-07-27 Japan Res Dev Corp Semiconductor crystal growth apparatus
EP0229633A2 (en) * 1986-01-08 1987-07-22 Gregory A. Roche Apparatus and method for laser-induced chemical vapor deposition

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Publication number Publication date
GB8917097D0 (en) 1989-09-13
GB2234529B (en) 1993-06-02

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020726