Radio frequency transistor amplifiers having self-aligned double implanted source/drain regions for improved on-resistance performance and related methods

Abstract

A HEMT transistor has a semiconductor layer structure that comprises a Group III nitride-based channel layer and a higher bandgap Group III nitride-based barrier layer on the channel layer. A gate finger and first and second source/drain contacts are provided on the semiconductor layer structure. A first source/drain region is provided in the semiconductor layer structure that includes a first implanted region that is underneath the first source/drain contact and a first auxiliary implanted region. A depth of the first implanted region is at least twice a depth of the first auxiliary implanted a region. The first source/drain region extends inwardly a first distance from a lower edge of an inner sidewall of the first source/drain contact, and extends outwardly a second smaller distance from a lower edge of an outer sidewall of the first source/drain contact.