US 5,296,395 A · Method of making a high electron mobility transistor

Abstract

A high electron mobility transistor is disclosed, which takes advantage of the increased mobility due to a two dimensional electron gas occurring in GaN/Al.sub.x Ga.sub.1-x N heterojunctions. These structures are deposited on basal plane sapphire using low pressure metalorganic chemical vapor deposition. The electron mobility of the heterojunction is approximately 620 cm.sup.2 per volt second at room temperature as compared to 56 cm.sup.2 per volt second for bulk GaN of the same thickness deposited under identical conditions. The mobility of the bulk sample peaked at 62 cm.sup.2 per volt second at 180.degree. K. and decreased to 19 cm.sup.2 per volt second at 77.degree. K. The mobility for the heterostructure, however, increased to a value of 1,600 cm.sup.2 per volt second at 77.degree. K. and saturated at 4.degree. K.

Claims4

Dependent claims

A method of making a transistor, comprising the steps of:

(a) depositing a buffer layer onto a substrate;
(b) depositing a layer of gallium nitride (GaN) onto the buffer layer;
(c) depositing a layer of Al.sub.x Ga.sub.1-x N on the gallium nitride layer, where x has a value of between 0 and 1;
(d) depositing a first metal layer onto the Al.sub.x Ga.sub.1-x N layer, thereby defining a source connection;
(e) depositing a second metallic layer onto the Al.sub.x Ga.sub.1-x N layer, thereby defining a drain region;
and
(f) depositing a third metal layer, onto the Al.sub.x Ga.sub.1-x N layer, the third metal layer, onto the Al.sub.x Ga.sub.1-x N layer, the third metal layer residing between the source region and the drain region, thereby defining a shottky barrier.

4 more elements

Dependencies are inferred from the claim text.

Method of making a high electron mobility transistor

Life of this patent

Method of making a high electron mobility transistor

Life of this patent

Abstract

Claims4