# US 8,785,976 B2 · Polarization super-junction low-loss gallium nitride semiconductor device

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- Number: US 8,785,976 B2
- Document ID: US8785976B2
- Status: Granted
- Kind: B2
- Application number: 13/639,075
- Filed: 2011-06-21
- Published: 2013-05-23
- Granted: 2014-07-22
- Earliest claimed: 2010-06-24
- Assignees: The University of Sheffield; Powdec K.K.
- Applicants: Akira Nakajima; Sankara Narayanan Ekkanath Madathil; Yasunobu Sumida; Hiroji Kawai
- Inventors: Akira Nakajima; Sankara Narayanan Ekkanath Madathil; Yasunobu Sumida; Hiroji Kawai
- Web page: https://patentgrep.com/patent/US8785976B2

## CPC

- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 8/00: Diodes (variable-capacitance diodes H10D1/64; gated diodes H10D12/00)
- H10D 8/053: {of heterojunction diodes or of tunnel diodes}
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- H10D 30/471: {High electron mobility transistors [HEMT] or high hole mobility transistors [HHMT]}
- H10D 30/475: {having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs}
- H10D 62/106: {having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions}
- H10D 62/357: {of FETs}
- H10D 64/411: {for FETs}
- H10D 8/60: Schottky-barrier diodes
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 64/111: {Field plates}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A low-loss GaN-based semiconductor device is provided. The semiconductor device has the InzGa1-zN layer (where 0≦z<1), the AlxGa1-xN layer (where 0<x<1), the InyGa1-yN layer (where 0≦y<1) and the p-type InwGa1-wN layer (where 0≦w<1) which are sequentially stacked on a base substrate of a C-plane sapphire substrate, etc. At a non-operating time, the two-dimensional hole gas is formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and the two-dimensional electron gas is formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer.

## Claims

### Claim 1

A semiconductor device, comprising:
an InzGa1-zN layer, where 0≦z<1,
an AlxGa1-xN layer, where 0<x<1, on the InzGa1-zN layer,
an InyGa1-yN layer, where 0≦y<1, on the AlxGa1-xN layer; and
a p-type InwGa1-wN layer, where 0≦w<1, on the InyGa1-yN layer,
a two-dimensional hole gas being formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and a two-dimensional electron gas being formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer at a non-operating time,
wherein the semiconductor device is a diode, a mesa is formed at least in the InyGa1-yN layer and the p-type InwGa1-wN layer, an anode electrode extends to the AlxGa1-xN layer adjacent to the mesa from the upper surface and the side surface on one end, and a cathode electrode extends to the AlxGa1-xN layer adjacent to the mesa from the upper surface and the side surface on the other end.

### Claim 2

A semiconductor device, comprising:
an InzGa1-zN layer, where 0≦z<1,
an AlxGa1-xN layer, where 0<x<1, on the InzGa1-zN layer,
an InyGa1-yN layer, where 0≦y<1, on the AlxGa1-xN layer; and
a p-type InwGa1-wN layer, where 0≦w<1, on the InyGa1-yN layer,
a two-dimensional hole gas being formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and a two-dimensional electron gas being formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer at a non-operating time,
wherein when the density of the two-dimensional hole gas is expressed as Ps and its unit is the cm−2, the density of the two-dimensional electron gas is expressed as Ns and its unit is the cm−2, and the thickness of the AlxGa1-xN layer is expressed as t and its unit is the cm, x, y, z, and t satisfy the following equations:
Ps=b1x+b2y−b3/t≧5×1012
Ns=b1x+b2z−b3/t≧5×1012
b1=5.66×1013 (cm−2)
b2=9.81×1013 (cm−2)
b3=1.89×107 (cm−1).

### Claim 3

A semiconductor device, comprising:
an InzGa1-zN layer, where 0≦z<1,
an AlxGa1-xN layer, where 0<x<1, on the InzGa1-zN layer,
an InyGa1-yN layer, where 0≦y<1, on the AlxGa1-xN layer; and
a p-type InwGa1-wN layer, where 0≦w<1, on the InyGa1-yN layer,
a two-dimensional hole gas being formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and a two-dimensional electron gas being formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer at a non-operating time,
wherein when the density of the two-dimensional hole gas is expressed as Ps and its unit is the cm−2, the density of the two-dimensional electron gas is expressed as Ns and its unit is the cm−2, and the thickness of the AlxGa1-xN layer is expressed as t and its unit is the cm, x, y, z, and t satisfy the following equations:
Ps=b1x+b2y−b3/t≧2×1012
Ns=b1x+b2z−b3/t≧2×1012
b1=5.66×1013 (cm−2)
b2=9.81×1013 (cm−2)
b3=1.89×107 (cm−1),
wherein when the thickness of the InyGa1-yN layer is expressed as q, the thickness of the p-type InwGa1-wN layer is expressed as r, the concentration of the p-type impurity of the p-type InwGa1-wN layer is expressed as NA, and the concentration of the n-type impurity of the AlxGa1-xN layer is expressed as ND, the following inequalities are satisfied:
x>0.08
t>15 nm
q>0 nm
r>8.0 nm
NA>1×1016 cm−3
ND<4×1018 cm−3.

### Claim 4

A semiconductor device, comprising:
an InzGa1-zN layer, where 0≦z<1,
an AlxGa1-xN layer, where 0<x<1, on the InzGa1-zN layer,
an InyGa1-yN layer, where 0≦y<1, on the AlxGa1-xN layer; and
a p-type InwGa1-wN layer, where 0≦w<1, on the InyGa1-yN layer,
a two-dimensional hole gas being formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and a two-dimensional electron gas being formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer at a non-operating time,
wherein when the density of the two-dimensional hole gas is expressed as Ps and its unit is the cm−2, the density of the two-dimensional electron gas is expressed as Ns and its unit is the cm−2, and the thickness of the AlxGa1-xN layer is expressed as t and its unit is the cm, x, y, z, and t satisfy the following equations:
Ps=b1x+b2y−b3/t≧2×1012
Ns=b1x+b2z−b3/t≧2×1012
b1=5.66×1013 (cm−2)
b2=9.81×1013 (cm−2)
b3=1.89×107 (cm−1),
wherein when the thickness of the InyGa1-yN layer is expressed as q, the thickness of the p-type InwGa1-wN layer is expressed as r, the concentration of the p-type impurity of the p-type InwGa1-wN layer is expressed as NA, and the concentration of the n-type impurity of the AlxGa1-xN layer is expressed as ND, the following inequalities are satisfied:
x>0.13
t>25 nm
q>1 nm
r>10 nm
NA>8×1017 cm−3
ND<3×1018 cm−3.

### Claim 5 (depends on 2)

The semiconductor device according to claim 2, further comprising an AluGa1-uN layer, where 0<u<1, u>x, between the InyGa1-yN layer and the AlxGa1-xN layer and/or between the InzGa1-zN layer and the AlxGa1-xN layer.

### Claim 6 (depends on 2)

The semiconductor device according to claim 2, wherein the semiconductor device is a field effect transistor, a mesa is formed at least in the InyGa1-yN layer and the p-type InwGa1-wN layer, a gate electrode and a source electrode are formed on the AlxGa1-xN layer on the same side part of the mesa, a drain electrode is formed on the AlxGa1-xN layer on the opposite side part of the mesa with regard to the gate electrode, and an electrode which is connected electrically with the source electrode or the gate electrode is formed on the p-type InwGa1-wN layer on the gate electrode side of the mesa.

### Claim 7 (depends on 2)

The semiconductor device according to claim 2, wherein the semiconductor device is a field effect transistor, a mesa is formed at least in the InyGa1-yN layer and the p-type InwGa1-wN layer, a gate electrode, a source electrode and a drain electrode are formed on the p-type InwGa1-wN layer of the mesa, and an electrode which is connected electrically with the gate electrode is formed on the AlxGa1-xN layer adjacent to the mesa.

### Claim 8

A semiconductor device, comprising:
an InzGa1-zN layer, where 0≦z<1,
an AlxGa1-xN layer, where 0<x<1, on the InzGa1-zN layer,
an InyGa1-yN layer, where 0≦y<1, on the AlxGa1-xN layer; and
a p-type InwGa1-wN layer, where 0≦w<1, on the InyGa1-yN layer,
a two-dimensional hole gas being formed in the InyGa1-yN layer in the vicinity part of a hetero-interface between the AlxGa1-xN layer and the InyGa1-yN layer, and a two-dimensional electron gas being formed in the InzGa1-zN layer in the vicinity part of a hetero-interface between the InzGa1-zN layer and the AlxGa1-xN layer at a non-operating time,
wherein when the density of the two-dimensional hole gas is expressed as Ps and its unit is the cm−2, the density of the two-dimensional electron gas is expressed as Ns and its unit is the cm−2, and the thickness of the AlxGa1-xN layer is expressed as t and its unit is the cm, x, y, z, and t satisfy the following equations:
Ps=b1x+b2y−b3/t≧2×1012
Ns=b1x+b2z−b3/t≧2×1012
b1=5.66×1013 (cm−2)
b2=9.81×1013 (cm−2)
b3=1.89×107 (cm−1),
wherein the semiconductor device is a diode, a mesa is formed at least in the InyGa1-yN layer and the p-type InwGa1-wN layer, an anode electrode is contacting the p-type InwGa1-wN layer of one end part of the mesa, and a cathode electrode on the AlxGa1-xN layer on the other end part of the mesa.