Process Development and Characterization of AlGaN/GaN Heterostructure Field-Effect Transistors

The fabrication of AlGaN/GaN HFETs entailed first developing fundamental processing techniques such as isolation etching, low-resistance drain/source ohmic contacts, and Schottky gate formation. These efforts along with related processing issues will be discussed. Devices were then fabricated on epitaxial layers grown on sapphire substrates and on n-type, p-type, and insulating SiC. While sapphire is the substrate of choice for the nitrides, SiC substrates are better suited for high-power devices due to their significantly higher thermal conductivity. The dc, RF, and high-temperature performance of transistors on sapphire and SiC were investigated to determine the performance similarities and differences between using the various substrates. Forming low-resistance ohmic contacts to the wide bandgap heterostructures is difficult and as a result limits the overall device performance. In an effort to improve drain-source contacts, gate recessing through the use of low-damage inductively coupled plasma reactive ion etching was pursued. A wet chemical etching process called photoelectrochemical etching was also investigated.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Ping, Andrew Taiann

Contributors dc:contributor

• Adesida, Ilesanmi

• Engineering, Electronics and Electrical

Language dc:language

eng

Identifier

(MiAaPQ)AAI9953111

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/81312