Enhancement-mode III-N devices, circuits, and methods

US7932539B2 · kind B2 · utility

Assignee

• The Hong Kong University of Science and Technology

Inventors

• Jing Chen · Hong Kong, CN
• Yong Cai · Fuzhou, CN
• Kei May Lau · Kowloon, CN

Key dates

• Filing date: Nov 29, 2006
• Grant date: Apr 26, 2011
• Expiry date: Jan 1, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/8503

Abstract

A method of fabricating AlGaN/GaN enhancement-mode heterostructure field-effect transistors (HFET) using fluorine-based plasma immersion or ion implantation. The method includes: 1) generating gate patterns; 2) exposing the AlGaN/GaN heterostructure in the gate region to fluorine-based plasma treatment with photoresist as the treatment mask in a self-aligned manner; 3) depositing the gate metal to the plasma treated AlGaN/GaN heterostructure surface; 4) lifting off the metal except the gate electrode; and 5) high temperature post-gate annealing of the sample. This method can be used to shift the threshold voltage of a HFET toward a more positive value, and ultimately convert a depletion-mode HFET to an enhancement-mode HFET (E-HFET).