Automatic P-N junction formation during growth of a heterojunction

Claim 2

A PROCESS FOR THE PREPARATION OF A P-N HOMOJUNCTION BETWEEN REGIONS OF DIFFERING CONDUCTIVITY IN A SEMICONDUCTOR SUBSTRATE AND A HETERJUNCTION AT THE SURFACE OF SAID SUBSTRATE COMPRISING GROWING ALUMINUM NITRIDE OR GALLIUM NITRIDE ON SUBSTRATE TO FORM SAID HETERJUNCTION WHEREBY GALLIUM ATOMS FROM SAID GALLIUM NITRIDE OR ALUMINUM ATOMS FROM SAID ALUMINUM NITRIDE DIFFUSE INTO SAID SUBSTRATE IN THE REGIONS OF SAID SUBSTRATE ADJACENT SAID ALUMINUM NITRIDE OR GALLIUM NITRIDE TO FORM SAID HOMOJUNCTION IN SAID SUBSTRATE.

Claim 3

The process of claim 1 wherein said semiconductor substrate is silicon, germanium, silicon carbide or germanium carbide.

Claim 4

The process of claim 1 wherin said semiconductor substrate is silicon.

Claim 5

The process of claim 3 wherein said semiconductor substrate is silicon and where said silicon is n-type silicon, at least in the area of said silicon semiconductor substrate adjacent said aluminum nitride or gallium nitride.

Claim 6

The process of claim 1 wherein prior to said growing of said gallium nitride or said aluminum nitride, siad process comprises forming a masking oxide layer on said semiconductor substrate and etching of said oxide layer thereby creating at least one area on said substrate uncovered by said oxide layer.

Claim 7

The process of claim 1 wherein said growing is utilizing a volatizable gallium compound and ammonia at a temperaure of from about 700*C to about 900*C. for about 15 minutes to about 2 hours.

Claim 8

The process of claim 1 wherein said growing is by sputtering of elemental aluminum or gallium in a reactive nitrogen atmosphere at a temperature of from about 0*C. to about 800*C. for from about 10 minutes to about 4 hours.

Claim 9

The process of claim 1 wherein said growing is by vacuum evaporation of elemental aluminum or elemental gallium in a reactive nitrogen atmosphere at a temperature of from about 0*C. to about 800*C. for a period of from about 10 minutes to about 4 hours.

Claim 10

A process for the prepartion of a p-n homojunction between regions of differing conductivity in a semiconductor substrate and a heterojunction at the surface of said substrate comprising growing aluminum nitride or gallium nitride on the substrate at a temperature sufficiently low that substantially no diffusion of aluminum or gallium atoms from said aluminum nitride or gAllium nitride into said substrate occurs, and subsequent to said growing, said process comprising additionally heating said substrate with said aluminum nitride or gallium nitride thereon at a temperature of from about 600*C. to about 800*C. for said gallium nitride and at temperatures from about 600*C. to about 1,000*C. for said aluminum nitride, under conditions preventing the dissociation of said aluminum nitride or gallium nitride and loss thereof.

Claim 11

A process for the prepartion of a p-n homojunction between regions of differing conductivity in a semiconductor substrate and a heterojunction at the surface of said substrate comprising growing aluminum nitride or gallium nitride on the substrate at a temperature sufficiently low that substantially no diffusion of aluminum or gallium atoms from said aluminum nitride or gAllium nitride into said substrate occurs, and subsequent to said growing, said process comprising additionally heating said substrate with said aluminum nitride or gallium nitride thereon at a temperature of from about 600*C. to about 800*C. for said gallium nitride and at temperatures from about 600*C. to about 1,000*C. for said aluminum nitride, under conditions preventing the dissociation of said aluminum nitride or gallium nitride and loss thereof.

Claim 12

The process of claim 9 wherein said temperature at which substantially no diffusion occurs is a temperature of from about room temperature to about 500*C.

Claim 13

A process for the preparation of a semiconductor device containing both a homojunction and a heterojunction comprising: forming on a semicondcutor substrate an oxide protective layer so as to create on said substrate areas of said substrate which are covered by said oxide layer and areas which are not covered by said oxide layer, said substrate having n-type characteristics at least in the areas of said substrate not covered by said oxide layer; growing a layer of aluminum nitride or gallium nitride on said coated substrate so as to form a layer of aluminum nitride or gallium nitride thereon, said growing of said aluminum nitride or gallium nitride layer being at a time and temperature such that gallium atoms from said gallium nitride or aluminum atoms from said aluminum nitride diffuse into said substrate in the regions of said substrate which are not covered by said protective oxide layer and adjacent said aluminum nitride or gallium nitride to form p-n junctions; and attaching electrical terminals to said gallium nitride or aluminum nitride layer and said substrate so as to electrically connected said heterojunction and said p-n junction in series.

Claim 14

A process for the preparation of a semiconductor device containing both a homojunction and a heterojunction comprising: forming on a semicondcutor substrate an oxide protective layer so as to create on said substrate areas of said substrate which are covered by said oxide layer and areas which are not covered by said oxide layer, said substrate having n-type characteristics at least in the areas of said substrate not covered by said oxide layer; growing a layer of aluminum nitride or gallium nitride on said coated substrate so as to form a layer of aluminum nitride or gallium nitride thereon, said growing of said aluminum nitride or gallium nitride layer being at a time and temperature such that gallium atoms from said gallium nitride or aluminum atoms from said aluminum nitride diffuse into said substrate in the regions of said substrate which are not covered by said protective oxide layer and adjacent said aluminum nitride or gallium nitride to form p-n junctions; and attaching electrical terminals to said gallium nitride or aluminum nitride layer and said substrate so as to electrically connected said heterojunction and said p-n junction in series.

Claim 15

The process of claim 11 wherein said semiconductor substrate is silicon, germanium, silicon carbide or germanium carbide.

Claim 16

The process of claim 11 wherein said semiconductor substrate is silicon.

Claim 17

The process of claim 11 where said growing time and temperature are chosen to minimize the diffusion which occurs and in which subsequent annealing is performed at a desired time and temperature to produce the diffusion to a desired depth.

Claim 18

A process for the preparation of shallow diffusion depths with very high surface concentrations comprising: growing a layer of aluminum nitride or gallium nitride onto the surface of a semiconductor substrate at a time and temperature chosen to result in diffusion of the aluminum or gallium from the nitride layer into said substrate to the desired depth.

Claim 19

A process for the preparation of shallow diffusion depths with very high surface concentrations comprising: growing a layer of aluminum nitride or gallium nitride onto the surface of a semiconductor substrate at a time and temperature chosen to result in diffusion of the aluminum or gallium from the nitride layer into said substrate to the desired depth.

Claim 20

The process of claim 15 in which said semiconductor substrate is silicon.

Claim 21

A process for the preparation of shallow diffusion depths with very high surface concentrations comprising: growing a layer of aluminum nitride or gallium nitride onto the surface of a semiconductor substrate at a time and temperature chosen to result in negligible diffusion of the aluminum or gallium from the nitride layer into said substrate; annealing said substrate with said nitride layer, subsequent to said growing of said nitride layer, at a time and temperature chosen to result in diffusion of the aluminum or gallium from said nitride layer into said substrate to the desired depth.

Claim 22

A process for the preparation of shallow diffusion depths with very high surface concentrations comprising: growing a layer of aluminum nitride or gallium nitride onto the surface of a semiconductor substrate at a time and temperature chosen to result in negligible diffusion of the aluminum or gallium from the nitride layer into said substrate; annealing said substrate with said nitride layer, subsequent to said growing of said nitride layer, at a time and temperature chosen to result in diffusion of the aluminum or gallium from said nitride layer into said substrate to the desired depth.

Claim 23

The process of claim 17 in which said semiconductor substrate is silicon.