Method of making buffer layers for III-V devices using solid phase epitaxy
AssigneeMassachusetts Institute of Technology
InventorsArthur R. Calawa, Frank W. Smith, Michael J. Manfra, Chang-Lee Chen
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Abstract
A new III-IV buffer material is described which is produced by low temperature growth of III-V compounds by MBE that has unique and desirable properties, particularly for closely spaced, submicron gate length active III-V semiconductor devices, such as HEMT's, MESFET's and MISFET's. In the case of the III-V material, GaAs, the buffer is grown under arsenic stable growth conditions, at a growth rate of 1 micron/hour, and at a substrate temperature preferably in the range of 150 to about 300.degree. C. The new material is crystalline, highly resistive, optically inactive, and can be overgrown with high quality III-V active layers.
Claims10
A method of making an intermediate optically inert, electrically insulating crystalline layer of GaAs material on a substrate for growth thereon of high quality crystalline films comprising the steps of:
- (a) forming in a chamber said crystalline layer of GaAs material by low temperature molecular beam deposition at less than 300.degree. C. of a flux of Ga and As molecular beam specie on a surface of a substrate formed of III-V materials;
- (b) subjecting said layer to a heat treatment in an ambient containing arsenic;
- (c) forming a thin stabilizing layer over said heat treated layer to minimize out diffusion of the arsenic.
A method of making GaAs device on a structure comprising the steps of:
- (a) forming in a chamber, a crystalline buffer layer of GaAs material by low temperature molecular beam deposition at below 300.degree. C. of a flux of Ga and As materials on a surface of a substrate formed from the group comprising III-V materials;
- (b) subjecting said layer to a heat treatment in an ambient containing arsenic;
- (c) forming a thin stabilizing layer of GaAs material over said heat treated layer to minimize out diffusion of the arsenic;
- (d) forming said GaAs device on said stabilizing layer.
A method of making an intermediate buffer structure for growth thereon of high quality crystalline electro-optical films comprising the steps of:
- (a) in a chamber, forming a crystalline buffer layer of thickness greater than 300.degree. .ANG. of material by low temperature molecular beam deposition at less than 300.degree. C. of a flux of Ga and As molecular beam specie on a surface of a substrate, which surface is comprised of materials from the same III-V group of materials as in the buffer layer;
- (b) subjecting said buffer layer to a heat treatment at less than 900.degree. C. in an ambient containing arsenic;
- (c) forming a thin stabilizing layer over said heat treated layer to minimize out diffusion of the arsenic;
- thereby to produce a stable buffer layer which is optically inert and electrically insulating.
A method of making a III-V device on a substrate comprising the steps of:
- (a) forming a buffer layer of III-V material by low temperature molecular beam deposition at less than 300.degree. C. of a flux of III-V molecules on said GaAs substrate in a chamber;
- (b) subjecting said layer to a heat treatment in an ambient containing As;
- (c) forming a thin stabilizing layer of III-V material over said heat treated layer to minimize out diffusion of the As;
- (d) forming said III-V device on said stabilizing layer.
Dependencies are inferred from the claim text.