Transistor with diamond gate

Patent metadata

Field	Value
Publication number	US-9466684-B2
Application number	US-201615080624-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Aug 30, 2013
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A field effect transistor having a diamond gate electrode and a process for forming the same. In some embodiments, the device is an AlGaN/GaN high-electron-mobility transistor (HEMT). The diamond gate electrode is formed so that it directly contacts the barrier layer. In some embodiments, the diamond gate electrode is formed from boron-doped nanocrystalline diamond (NCD), while in other embodiments, the diamond gate electrode is formed from single crystal diamond.

First claim

What is claimed is:

1. A method for forming a semiconductor device having a diamond gate electrode, comprising: forming a semiconductor material buffer layer on a substrate, the semiconductor material buffer layer having a first bandgap and being configured to provide electron transport in the semiconductor device; forming a semiconductor barrier layer on an upper surface of the semiconductor material buffer layer, the semiconductor barrier layer having a second bandgap, the second bandgap being wider than the first bandgap; depositing an ohmic metal layer on an upper surface of the semiconductor barrier layer and patterning the ohmic metal layer to provide an opening for a doped diamond gate electrode; and forming the diamond gate electrode, the diamond gate electrode being formed from doped diamond material grown directly on the upper surface of the semiconductor barrier layer, the dopant in the doped diamond material being concentrated at a nucleation interface between the doped diamond material and the upper surface of the semiconductor barrier layer; wherein the diamond gate electrode is formed so that at least a portion of the diamond gate electrode is in direct contact with the upper surface of the semiconductor barrier layer.

2. The method according to claim 1 , wherein the doped diamond material is p+-doped nanocrystalline diamond (NCD).

3. The method according to claim 1 , wherein the doped diamond material is doped with boron, potassium, sodium, and/or aluminum.

4. The method according to claim 1 , further comprising depositing a passivation layer on an upper surface of the semiconductor barrier layer; and patterning the passivation layer before formation of the diamond gate electrode to provide an opening for the diamond gate electrode, at least a portion of the diamond gate electrode being formed directly on and being in direct contact with the upper surface of the semiconductor barrier layer.

5. The method according to claim 4 , wherein a portion of the diamond gate electrode is formed on the passivation layer.

6. The method according to claim 1 , further comprising depositing an electrically conductive cap on an upper surface of the diamond gate electrode and patterning the doped diamond material forming the diamond gate electrode according to a pattern defined by the electrically conductive cap.

7. The method according to claim 6 , wherein the electrically conductive cap is left on the upper surface of the diamond gate electrode after patterning is completed.

Assignees

• Us Navy

Inventors

• Koehler Andrew D
• Anderson Travis J
• Tadjer Marko J
• Hobart Karl D
• Feygelson Tatyana I

Classifications

• H10D62/343

  Gate regions of field-effect devices having PN junction gates · CPC title

• H10D64/602 Primary

  Heterojunction gate electrodes for FETs · CPC title

• H10D62/8503

  Nitride Group III-V materials, e.g. AlN or GaN · CPC title

• H10D62/824

  comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions · CPC title

• H10D62/82

  Heterojunctions · CPC title