US6849882B2
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Group-III nitride based high electron mobility transistor (HEMT) with barrier/spacer layer
Assignee: MACOM Technology Solutions Holdings Inc
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Filing: 2002-03-19
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Granted: 2005-02-01
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Expires: 2022-03-19
Abstract
Abstract A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an Al y Ga 1−y N (y=1 or y 1) layer on the GaN buffer layer. An Al x Ga 1−x N (0≦x≦0.5) barrier layer on to the Al y Ga 1−y N layer, opposite the GaN buffer layer, Al y Ga 1−y N layer having a higher Al concentration than that of the Al x Ga 1−x N barrier layer. A preferred Al y Ga 1−y N layer has y=1 or y ˜ 1 and a preferred Al x Ga 1−x N barrier layer has 0≦x≦0.5. A 2DEG forms at the interface between the GaN buffer layer and the Al y Ga 1−y N layer. Respective source, drain and gate contacts are formed on the Al x Ga 1−x N barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the Al y Ga 1−y N layer and a nucleation layer between the Al x Ga 1−x N buffer layer and the substrate.
Inventors
- 👤 Prashant Chavarkar
- 👤 Ioulia P. Smorchkova
- 👤 Stacia Keller
- 👤 Umesh Mishra
- 👤 Wladyslaw Walukiewicz
- 👤 Yifeng Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:17
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/473; H10D30/4732; H10D62/00; H10D62/80; H10D62/85; H10D62/8503
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
85 words
A high electron mobility transistor (HEMT), comprising: a GaN buffer layer; an Al y Ga 1−y N (y>0.5) layer on said GaN buffer layer; an Al x Ga 1−x N barrier layer on said Al y Ga 1−y N layer opposite said GaN buffer layer, said Al y Ga 1−y N layer having a higher Al content than said Al x Ga 1−x N barrier layer; and a 2DEG at the interface between said GaN buffer layer and said Al y Ga 1−y N layer.
Claim 2
Dependent Claim
85 words
A high electron mobility transistor (HEMT), comprising: a GaN buffer layer; an Al y Ga 1−y N (y>0.5) layer on said GaN buffer layer; an Al x Ga 1−x N barrier layer on said Al y Ga 1−y N layer opposite said GaN buffer layer, said Al y Ga 1−y N layer having a higher Al content than said Al x Ga 1−x N barrier layer; and a 2DEG at the interface between said GaN buffer layer and said Al y Ga 1−y N layer.
Claim 3
Dependent Claim
23 words
The HEMT of claim 1 , wherein said Al y Ga 1−y N layer comprises Al y Ga 1−y N (y=1 or y≈1).
Claim 4
Dependent Claim
22 words
The HEMT of claim 1 , wherein said Al x Ga 1−x N barrier layer comprises AL x Ga 1−x N (0≦x≦0.5).
Claim 5
Dependent Claim
23 words
The HEMT of claim 1 , further comprising respective source, drain and gate contacts on said Al x Ga 1−x N barrier layer.
Claim 6
Dependent Claim
41 words
The HEMT of claim 1 , further comprising a substrate adjacent to said buffer layer, opposite said Al y Ga 1−y N layer, said substrate made from a material from the group consisting of sapphire, silicon carbide, gallium nitride and silicon.
Claim 7
Dependent Claim
19 words
The HEMT of claim 1 , further comprising a nucleation layer between said GaN buffer layer and said substrate.
Claim 8
Dependent Claim
26 words
The HEMT of claim 4 , wherein said source and drain contacts are made of an alloy from the group consisting of titanium, aluminum, and nickel.
Claim 9
Dependent Claim
29 words
The HEMT of claim 4 , wherein said gate made of a material from the group consisting of titanium, platinum, chromium, alloys of titanium and tungsten, and platinum silicide.
Claim 10
Dependent Claim
18 words
The HEMT of claim 1 , wherein said GaN buffer layer is less than approximately 5 μm thick.
Claim 11
Dependent Claim
21 words
The HEMT of claim 1 , wherein said Al y Ga 1−y N layer is less than approximately 50 Å thick.
Claim 12
Dependent Claim
22 words
The HEMT of claim 1 , wherein said Al x Ga 1−x N barrier layer is approximately 100 to 1000 Å thick.
Claim 13
Dependent Claim
24 words
The HEMT of claim 4 , wherein the resistance under said gate contact is greater than the resistance under said source and drain contacts.
Claim 14
Dependent Claim
16 words
The HEMT of claim 4 , wherein said barrier layer is thinner under said gate contact.
Claim 15
Dependent Claim
13 words
The HEMT of claim 1 , wherein said layers can be fabricated digitally.
Claim 16
Dependent Claim
99 words
A group III nitride based high electron mobility transistor (HEMT), comprising: a semiconductor buffer layer; a high polarization semiconductor layer on said buffer layer; a semiconductor barrier layer on said high polarization layer so that said high polarization layer is sandwiched between said buffer and barrier layers, each of said layers having a non-zero total polarization pointing in the same direction, the magnitude of said polarization in said high polarization layer higher than the polarization of said buffer and barrier layers; and a two dimensional electron gas at the interface between said buffer layer and said high polarization layer.
Claim 17
Dependent Claim
99 words
A group III nitride based high electron mobility transistor (HEMT), comprising: a semiconductor buffer layer; a high polarization semiconductor layer on said buffer layer; a semiconductor barrier layer on said high polarization layer so that said high polarization layer is sandwiched between said buffer and barrier layers, each of said layers having a non-zero total polarization pointing in the same direction, the magnitude of said polarization in said high polarization layer higher than the polarization of said buffer and barrier layers; and a two dimensional electron gas at the interface between said buffer layer and said high polarization layer.
Claim 18
Dependent Claim
19 words
The HEMT of claim 15 , further comprising respective source, drain and gate contacts that contact said barrier layer.
Claim 19
Dependent Claim
38 words
The HEMT of claim 15 , further comprising a substrate adjacent to said buffer layer, opposite said high polarization layer, said substrate made from a material from the group consisting of sapphire, silicon carbide, gallium nitride and silicon.
Claim 20
Dependent Claim
18 words
The HEMT of claim 15 , further comprising a nucleation layer between said buffer layer and said substrate.
Claim 21
Dependent Claim
14 words
The HEMT of claim 15 , wherein said buffer layer is made of GaN.
Claim 22
Dependent Claim
16 words
The HEMT of claim 15 , wherein said buffer layer is less than 5 μm thick.
Claim 23
Dependent Claim
23 words
The HEMT of claim 15 , wherein said high polarization semiconductor layer is made of Al y Ga 1−y N (y=1 or y≈1).
Claim 24
Dependent Claim
17 words
The HEMT of claim 15 , wherein said high polarization layer is less than 50 Å thick.
Claim 25
Dependent Claim
18 words
The HEMT of claim 15 , wherein said barrier layer made of Al x Ga 1−x N (0≦x≦0.5).
Claim 26
Dependent Claim
16 words
The HEMT of claim 15 , wherein said barrier layer is 100 to 1000 Å thick.
Claim 27
Dependent Claim
122 words
A high electron mobility transistor (HEMT), comprising: a bottom layer of Group III nitride semiconductor material; a middle layer of Group III nitride semiconductor material on said bottom layer, wherein said middle layer can comprise one or more Group III elements one of which is Al; a top layer of Group III nitride semiconductor material on said middle layer, opposite said bottom layer, wherein said top layer can comprise one or more Group III elements, said middle layer having Al concentration that is higher than 50% and said Al in said middle layer also having a concentration that is higher than the concentration of any Al in said top layer; and a 2DEG at the interface between said middle and bottom layer.
Claim 28
Dependent Claim
122 words
A high electron mobility transistor (HEMT), comprising: a bottom layer of Group III nitride semiconductor material; a middle layer of Group III nitride semiconductor material on said bottom layer, wherein said middle layer can comprise one or more Group III elements one of which is Al; a top layer of Group III nitride semiconductor material on said middle layer, opposite said bottom layer, wherein said top layer can comprise one or more Group III elements, said middle layer having Al concentration that is higher than 50% and said Al in said middle layer also having a concentration that is higher than the concentration of any Al in said top layer; and a 2DEG at the interface between said middle and bottom layer.
Claim 29
Dependent Claim
19 words
The HEMT of claim 25 , further comprising respective source, drain and gate contacts that contact said top layer.
Claim 30
Dependent Claim
19 words
The HEMT of claim 25 , further comprising a substrate adjacent to said bottom layer, opposite said top layer.
Claim 31
Dependent Claim
18 words
The HEMT of claim 25 , further comprising a nucleation layer between said bottom layer and said substrate.
Claim 32
Dependent Claim
21 words
The HEMT of claim 25 , wherein said bottom layer is made of GaN and is less than 5 μm thick.
Claim 33
Dependent Claim
28 words
The HEMT of claim 25 , wherein said middle layer is made of Al y Ga 1−y N (y=1 or y≈1) and is less than 50 Å thick.
Claim 34
Dependent Claim
25 words
The HEMT of claim 25 , wherein said barrier layer made of Al x Ga 1−x N (0≦x≦0.5) and is 100 to 1000 Å thick.
Claim 35
Dependent Claim
24 words
The HEMT of claim 26 , wherein the resistance under said gate contact is greater than the resistance under said source and drain contacts.
Claim 36
Dependent Claim
16 words
The HEMT of claim 26 , wherein said barrier layer is thinner under said gate contact.
Claim 37
Dependent Claim
13 words
The HEMT of claim 25 , wherein said layers can be fabricated digitally.
References Cited (Backward Citations)
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