Integrated heterostructures of group III-V nitride semiconductor materials including epitaxial ohmic contact comprising multiple quantum well

Claim 2

An ohmic contact for a semiconductor device formed of Group III-V nitride compound semiconductor materials and including a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type, said ohmic contact comprising: a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 3

An ohmic contact according to claim 1 wherein said thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases linearly or nonlinearly from adjacent said first layer to opposite said first layer.

Claim 4

An ohmic contact according to claim 2 wherein the thickness of said layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof remains constant from adjacent said first layer to opposite said first layer.

Claim 5

An ohmic contact according to claim 1 wherein said conductor layer comprises metal.

Claim 6

An ohmic contact for a semiconductor device formed of Group III-V nitride compound semiconductor materials and including a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type, said ohmic contact comprising: a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 7

An ohmic contact for a semiconductor device formed of Group III-V nitride compound semiconductor materials and including a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type, said ohmic contact comprising: a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 8

An ohmic contact according to claim 5 wherein said thickness of said layers of gallium nitride or an alloy thereof increases linearly or nonlinearly from adjacent said first layer to opposite said first layer.

Claim 9

An ohmic contact according to claim 6 wherein the thickness of said layers of aluminum nitride or aluminum gallium nitride remains constant from adjacent said first layer to opposite said first layer.

Claim 10

An ohmic contact according to claim 5 wherein said conductor layer comprises metal.

Claim 11

An ohmic contact according to claim 5 wherein said first layer comprises aluminum gallium nitride, and wherein the concentration of gallium relative to aluminum in said first layer is same as the concentration of gallium relative to aluminum in said second layer adjacent said first layer.

Claim 12

An integrated heterostructure device of Group III-V nitride compound semiconductor materials, comprising: a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 13

An integrated heterostructure device of Group III-V nitride compound semiconductor materials, comprising: a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 14

An integrated heterostructure device according to claim 10 wherein said thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases linearly or nonlinearly from adjacent said first layer to opposite said first layer.

Claim 15

An integrated heterostructure device according to claim 11 wherein the thickness of said layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof remains constant from adjacent said first layer to opposite said first layer.

Claim 16

An integrated heterostructure device according to claim 10 wherein said conductor layer comprises metal.

Claim 17

An integrated heterostructure device according to claim 10 further comprising: an active device region on said first layer.

Claim 18

An integrated heterostructure device according to claim 14 further comprising: a fourth layer comprising said first binary Group III-V nitride compound semiconductor material or an alloy thereof, on said active device region, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped opposite said predetermined conductivity type; a fifth layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped opposite said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said fourth layer to opposite said fourth layer; a sixth layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said fifth layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped opposite said predetermined conductivity type; and a second conductor layer on said sixth layer.

Claim 19

An integrated heterostructure device according to claim 10 further comprising a second conductor layer, spaced apart from said first layer to define a carrier emission path from said first layer to said second conductor layer.

Claim 20

An integrated heterostructure device of Group III-V nitride compound semiconductor materials, comprising: a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 21

An integrated heterostructure device of Group III-V nitride compound semiconductor materials, comprising: a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 22

An integrated heterostructure device according to claim 17 wherein said thickness of said layers of gallium nitride or an alloy thereof increases linearly or nonlinearly from adjacent said first layer to opposite said first layer.

Claim 23

An integrated heterostructure device according to claim 18, wherein the thickness of said layers of aluminum nitride, aluminum gallium nitride or an alloy thereof remains constant from adjacent said first layer to opposite said first layer.

Claim 24

An integrated heterostructure device according to claim 17 wherein said conductor layer comprises metal.

Claim 25

An integrated heterostructure device according to claim 17 wherein said first layer comprises aluminum gallium nitride, and wherein the concentration of gallium relative to aluminum in said first layer is same as the concentration of gallium relative to aluminum in said second layer adjacent said first layer.

Claim 26

An integrated heterostructure device according to claim 17 further comprising: an active device region on said first layer.

Claim 27

An integrated heterostructure device according to claim 22 further comprising: a fourth layer comprising aluminum nitride or aluminum gallium nitride, on said active device region, and which is doped opposite said predetermined conductivity type; a fifth layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said fourth layer, which is doped opposite said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said fourth layer to opposite said fourth layer; a sixth layer comprising gallium nitride or an alloy thereof on said fifth layer, and doped opposite said predetermined conductivity type; and a second conductor layer on said sixth layer.

Claim 28

An integrated heterostructure device according to claim 17 further comprising a second conductor layer, spaced apart from said first layer to define a carrier emission path from said first layer to said second conductor layer.

Claim 29

An integrated heterostructure device comprising: a substrate comprising monocrystalline semiconductor material; a buffer layer comprising a non-nitride monocrystalline material on said substrate; and an integrated heterostructure of Group III-V nitride compound semiconductor materials on said buffer layer, wherein said integrated heterostructure comprises an ohmic contact of Group III-V nitride compound semiconductor materials and wherein said ohmic contact comprises: a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well including alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; and a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein said third layer is on said buffer layer.

Claim 30

An integrated heterostructure device comprising: a substrate comprising monocrystalline semiconductor material; a buffer layer comprising a non-nitride monocrystalline material on said substrate; and an integrated heterostructure of Group III-V nitride compound semiconductor materials on said buffer layer, wherein said integrated heterostructure comprises an ohmic contact of Group III-V nitride compound semiconductor materials and wherein said ohmic contact comprises: a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well including alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; and a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein said third layer is on said buffer layer.

Claim 31

An integrated heterostructure device comprising: a substrate comprising monocrystalline silicon carbide; a buffer layer comprising monocrystalline zinc oxide on said substrate; and an integrated heterostructure of Group III-V nitride compound semiconductor materials on said buffer layer, wherein said integrated heterostructure further comprises an ohmic contact of Group III-V nitride compound semiconductor materials and wherein said ohmic contact comprises: a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type, wherein said third layer is on said buffer layer.

Claim 32

An integrated heterostructure device comprising: a substrate comprising monocrystalline silicon carbide; a buffer layer comprising monocrystalline zinc oxide on said substrate; and an integrated heterostructure of Group III-V nitride compound semiconductor materials on said buffer layer, wherein said integrated heterostructure further comprises an ohmic contact of Group III-V nitride compound semiconductor materials and wherein said ohmic contact comprises: a first layer comprising aluminum nitride or aluminum gallium nitride, and which is doped a predetermined conductivity type; a second layer comprising a multiple quantum well of alternating layers of aluminum nitride or aluminum gallium nitride, and gallium nitride or an alloy thereof on said first layer, which is doped said predetermined conductivity type, wherein the thickness of said layers of gallium nitride or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising gallium nitride or an alloy thereof on said second layer, and doped said predetermined conductivity type, wherein said third layer is on said buffer layer.

Claim 33

A bipolar transistor, comprising: a base, an emitter and a collector, each of which includes a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen; and an ohmic contact for each of said base, said emitter and said collector, each ohmic contact comprising: a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer; and a conductor layer on said third layer.

Claim 34

A bipolar transistor, comprising: a base, an emitter and a collector, each of which includes a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen; and an ohmic contact for each of said base, said emitter and said collector, each ohmic contact comprising: a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer; and a conductor layer on said third layer.

Claim 35

A bipolar transistor according to claim 27 wherein said base, said emitter and said collector each comprise a Group III-V nitride compound semiconductor material.

Claim 36

A heterojunction bipolar transistor according to claim 27 wherein said base and said collector each comprise silicon carbide.

Claim 37

A field effect transistor comprising: spaced apart source and drain regions and a channel region therebetween; a gate adjacent said channel, said gate including a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; and an ohmic contact for said gate, said ohmic contact comprising: a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 38

A field effect transistor comprising: spaced apart source and drain regions and a channel region therebetween; a gate adjacent said channel, said gate including a first layer comprising a first binary Group III-V nitride compound semiconductor material or an alloy thereof, said first binary Group III-V nitride compound semiconductor material or an alloy thereof comprising a first Group III element and nitrogen, and which is doped a predetermined conductivity type; and an ohmic contact for said gate, said ohmic contact comprising: a second layer comprising a multiple quantum well including alternating layers of said first binary Group III-V nitride compound semiconductor material or an alloy thereof, and a second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said first layer, said alternating layers of said first binary group III-V nitride compound semiconductor material or an alloy thereof and said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type, wherein the thickness of said layers of said second binary Group III-V nitride compound semiconductor material or an alloy thereof increases from adjacent said first layer to opposite said first layer; a third layer comprising said second binary Group III-V nitride compound semiconductor material or an alloy thereof, on said second layer, said second binary Group III-V nitride compound semiconductor material or an alloy thereof being doped said predetermined conductivity type; and a conductor layer on said third layer.

Claim 39

A field effect transistor according to claim 30 wherein said channel region includes a layer of undoped ternary Group III-V nitride compound semiconductor material, to produce a modulation doped field effect transistor, and wherein said first layer is on said layer of undoped ternary Group III-V nitride compound semiconductor material.