TOP > 外国特許検索 > Opto-electronic and electronic devices using N-face or M-plane GaN substrate prepared with ammonothermal growth

Opto-electronic and electronic devices using N-face or M-plane GaN substrate prepared with ammonothermal growth 実績あり

外国特許コード F110003780
整理番号 E06732US1
掲載日 2011年7月4日
出願国 アメリカ合衆国
出願番号 76562907
公報番号 20080001165
公報番号 7755172
出願日 平成19年6月20日(2007.6.20)
公報発行日 平成20年1月3日(2008.1.3)
公報発行日 平成22年7月13日(2010.7.13)
優先権データ
  • 60/815,507P (2006.6.21) US
発明の名称 (英語) Opto-electronic and electronic devices using N-face or M-plane GaN substrate prepared with ammonothermal growth 実績あり
発明の概要(英語) A method for growing III-V nitride films having an N-face or M-plane using an ammonothermal growth technique.
The method comprises using an autoclave, heating the autoclave, and introducing ammonia into the autoclave to produce smooth N-face or M-plane Gallium Nitride films and bulk GaN.
従来技術、競合技術の概要(英語) BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is related to a method and materials for growing N-face Gallium Nitride (GaN) or M-plane Gallium Nitride using ammonothermal growth techniques.
2. Description of the Related Art
The usefulness of gallium nitride (GaN) and its ternary and quaternary alloys incorporating aluminum and indium (AlGaN, InGaN, AlINGaN) has been well established for fabrication of visible and ultraviolet opto-electronic devices and high-power electronic devices.
These devices are typically grown epitaxially on heterogeneous substrates, such as sapphire and silicon carbide, by Vapor Phase Epitaxy (VPE) techniques such as Metal-Organic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE).
The growth of device layers is usually initiated by growing a buffer layer on the substrate in the MOCVD or MBE reactor.
The buffer layer provides a smooth surface of GaN or AlN suitable for successive growth of device layers.
However, the buffer layer is usually a Ga-polar (Ga-face) surface, because growth along the N-polar (N-face) direction results in a rough surface in the VPE growth phase.
Commercially available GaN-based devices are all grown on Ga-polar surface (Gallium-face of the C-plane, also known as the (0001) plane).
Recently, however, several studies have pointed out many benefits of N-polar (the Nitrogen-face of the C-plane, also known as the (000-1) plane) devices.
Also, it has been pointed out that devices grown on M-plane, also known as the {10-10} plane have further advantages over Ga-polar or N-polar devices.
One major benefit of N-polar (N-face) growth is for p-type doping.
In Ga-polar (Ga-face) growth of Mg-doped GaN, the film polarity locally starts to invert to the N-polar (N-face) direction.
This phenomenon is known as inversion domains when the concentration of Mg exceeds a certain limit.
The inversion domains deteriorate the surface smoothness; therefore, a Ga-polar (Ga-face) film is limited in its hole concentrations.
Since high Mg doping favors N-polar (N-face) growth, using a N-polar (N-face) substrate is expected to attain higher Mg concentrations, and thus higher hole concentrations.
Opto-electronic devices with high p-type conduction will improve their efficiency by decreasing series resistance of the devices.
A second major benefit is the inverted polarization charge.
Although GaN-based High Electron Mobility Transistors (HEMTs) are currently available, their usage is very limited due to many unsolved problems.
GaN-based HEMTs currently available have high gate leakage and are typically depletion mode devices.
Transistors grown on N-face GaN would realize low gate leakage devices, devices that operate in enhancement mode (normally off mode), are crucial for power switching devices, low dispersion devices, and improved carrier confinement.
One of the major benefits of M-plane optical devices is the higher emission efficiency due to absence of polarization field.
Another major benefit of M-plane optical devices is that the optically active layer can contain more In, allowing longer wavelength emission.
This enables to realize green, yellow, even red color LEDs.
Despite these benefits, current technology is limited to Ga-polar (Ga-face) devices because of the poor surface smoothness of N-polar (N-face) surface or M-plane surface.
Therefore new technology to attain a smooth surface of N-polar (N-face) or M-plane GaN is needed to realize the next generation of high-performance devices such as ultra-high bright LEDs, low threshold current Laser Diodes (LDs), high-power high-speed signal transistors and high-power switching transistors.

特許請求の範囲(英語) [claim1]
1. A GaN layer overlaid on an N-polar surface of a GaN substrate, wherein the GaN substrate is made from a GaN bulk crystal grown ammonothermally on a GaN seed and the N-polar surface as grown is smoother than an as-grown Ga-polar surface of the ammonothermally grown GaN bulk crystal.
[claim2]
2. The GaN layer of claim 1, wherein the GaN layer is grown under pressure less than 760 Torr.
[claim3]
3. The GaN layer of claim 1, further comprising an AlGaN layer overlaid on an N-polar surface of the GaN layer, and a second GaN layer overlaid on the AlGaN layer, wherein electrons are induced at the interface between the AlGaN layer and the second GaN layer on the second GaN layer side in order to fabricate an electronic device.
[claim4]
4. An opto-electronic device comprising: a plurality of n-type group III nitride layers overlaid on an N-polar surface of a GaN substrate, wherein the GaN substrate is made from a GaN bulk crystal grown ammonothermally on a GaN seed and the N-polar surface as grown is smoother than an as-grown Ga-polar surface of the ammonothermally grown GaN bulk crystal;
at least one group III nitride light-emitting active layer overlaid on the plurality of n-type group III nitride layers; and
at least one p-type group III nitride layer having an Mg doping overlaid on the active layers.
[claim5]
5. The opto-electronic device in claim 4, wherein a concentration of the Mg-doped layer is more than 1021 cm-3.
[claim6]
6. The opto-electronic device of claim 5, wherein a thickness of the Mg-doped layer is more than 0.1 micron.
[claim7]
7. An electronic device comprising: a GaN layer, wherein the GaN layer is overlaid on a surface other than a C-plane of a GaN substrate, the GaN substrate is made from a GaN bulk crystal grown ammonothermally on a GaN seed, and the surface as grown is smoother than an as-grown Ga-polar surface of the ammonothermally grown GaN bulk crystal.
[claim8]
8. The electronic device of claim 7, further comprising an AlGaN layer overlaid on a surface of the GaN layer, and a second GaN layer overlaid on the AlGaN layer, wherein electrons are induced at the interface between the AlGaN layer and the second GaN layer on the second GaN layer side.
[claim9]
9. The electronic device of claim 7 wherein the surface of the GaN substrate is an M-plane {10-10}surface.
[claim10]
10. The electronic device of claim 7 wherein the surface of the GaN substrate is an A-plane {11-20}surface.
[claim11]
11. The electronic device of claim 7 wherein the surface of the GaN substrate is a {10-11}surface.
[claim12]
12. The electronic device of claim 7 wherein the surface of the GaN substrate is a {10-1-1}surface.
[claim13]
13. The electronic device of claim 7 wherein the surface of the GaN substrate is a {11-22}surface.
[claim14]
14. The electronic device of claim 7 wherein the surface of the GaN substrate is a {11-2-2}surface.
[claim15]
15. An opto-electronic device comprising: a GaN substrate having a surface other than a C-plane, wherein the GaN substrate is made from a GaN bulk crystal grown ammonothermally on a GaN seed and the surface as grown is smoother than an as-grown Ga-polar surface of the ammonothermally grown GaN bulk crystal;
a plurality of n-type group III nitride layers overlaid on the surface of the GaN substrate;
at least one group III nitride light-emitting active layer overlaid on the plurality of n-type group III nitride layers; and
at least one p-type group III nitride layer having an Mg doping overlaid on the active layer.
[claim16]
16. The opto-electronic device in claim 15, wherein a concentration of the Mg-doped layer is more than 1021 cm-3.
[claim17]
17. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is an M-plane {10-10}surface.
[claim18]
18. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is an A-plane {11-20}surface.
[claim19]
19. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is a {10-11}surface.
[claim20]
20. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is a {10-1-1}surface.
[claim21]
21. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is a {11-22}surface.
[claim22]
22. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is a {11-2-2}surface.
[claim23]
23. The opto-electronic device of claim 15 wherein the surface of the GaN substrate is a {20-21}surface.
  • 発明者/出願人(英語)
  • HASHIMOTO TADAO
  • SATO HITOSHI
  • NAKAMURA SHUJI
  • SILVERBROOK RESEARCH
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
国際特許分類(IPC)
米国特許分類/主・副
  • 257/627
  • 257/64
  • 257/103
  • 257/192
  • 257/628
  • 257/E21.036
  • 257/E21.233
  • 257/E29.003
  • 257/E29.004
  • 257/E29.246
  • 257/E31.04
  • 257/E33.003
  • 257/E33.034
  • 438/150
  • 438/168
  • 438/187
  • 438/198
  • 438/973
参考情報 (研究プロジェクト等) ERATO NAKAMURA Inhomogeneous Crystal AREA
ライセンスをご希望の方、特許の内容に興味を持たれた方は、問合せボタンを押してください。

PAGE TOP

close
close
close
close
close
close