High electron mobility transistor and power amplifier

• US 6,489,628 B1
• Filed: 06/29/2000
• Issued: 12/03/2002
• Est. Priority Date: 06/30/1999
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Morizuka, Mayumi
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): TRAN, MAI HUONG C
• Application Number:
  US09/606,015
• Time in Patent Office: 887 Days
• Field of Search: 257/183.1, 257/15, 257/192, 257/96, 257/190
• US Class Current: 257/12
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/7781 with inverted single heterostructure, i.e. with active layer formed on top of wide bandgap layer, e.g. IHEMT

Abstract

According to this invention, a group III nitride inverted high electron mobility transistor, and a power amplifier using the same are provided. A transistor and power amplifier according to this invention are characterized in that the lattice constant of a bulk of a donor layer is larger than that of an underlayer containing a group III nitride compound semiconductor material, or the donor layer is made of impurity-doped Al_yGa_(1−y)N, the underlayer is made of undoped Al_xGa_(1−x)N, and x and y satisfy an inequality 0≦y<x≦1.

Claims

1. A group III nitride inverted high electron mobility transistor comprising:

an underlayer comprising a first group III nitride compound semiconductor material;

a donor layer formed on said underlayer and comprising a second group III nitride compound semiconductor material, a lattice constant of a bulk of said donor layer being larger than a lattice constant of said underlayer;

a channel layer formed on said donor layer and comprising a third group III nitride compound semiconductor material; and

gate, source, and drain electrodes formed on said channel layer,

wherein the first group III nitride compound semiconductor material is Al_xGa<sub>(1−

x)</sub>N, the second group III nitride compound semiconductor material is Al_yGa<sub>(1−

y)</sub>N, x and y satisfy an inequality of 0≦

y<

x≦

1, and the third group III nitride compound semiconductor material is GaN.

2. A transistor according to claim 1, further comprising an Al_yGa₍₁₋

y)N spacer layer between said donor layer and said channel layer.

3. A transistor according to claim 1, further comprising a substrate and a nucleation layer formed on said substrate, and wherein said underlayer is formed by crystal growth, and said nucleation layer provides a nucleus for the crystal growth.

4. A group III nitride inverted high electron mobility transistor comprising:

an underlayer comprising a first group III nitride compound semiconductor material;

a donor layer formed on said underlayer and comprising a second group III nitride compound semiconductor material, a lattice constant of a bulk of said donor layer being larger than a lattice constant of said underlayer;

a channel layer formed on said donor layer and comprising a third group III nitride compound semiconductor material; and

gate, source, and drain electrodes formed on said channel layer,

wherein the first group III nitride compound semiconductor material is Al_xGa<sub>(1−

x)</sub>N, the second group III nitride compound semiconductor material is GaN, the third group III nitride compound semiconductor material is In_zGa<sub>(1−

z)</sub>N, and x and z respectively satisfy the inequalities 0<

x<

0 and 0<

z<

1.

5. A transistor according to claim 4, further comprising a GaN spacer layer between said donor layer and said channel layer.

6. A transistor according to claim 4, further comprising a substrate and a nucleation layer formed on said substrate,

wherein said underlayer is formed by crystal growth, and said nucleation layer provides a nucleus for the crystal growth.