Oct 17 (Mon) @ 1:30pm: "GaN/AlGaN Superlattice Based Hole Channel FinFET," Aditya Raj, ECE PhD Defense

Zoom Meeting – https://ucsb.zoom.us/j/87804558140

Abstract

There is a strong need for a large band gap pFET device with good performance for an efficient high voltage CMOS platform for power conversion applications. GaN HEMTs are already commercially used in high-power conversion systems. However, the performance of the GaN pFETs have not been attractive enough for a GaN based CMOS power conversion technology.

Work in this dissertation focuses on improving the on-current of hole channel GaN transistors while maintaining normally off operation. Lower hole mobility requires a much higher hole channel charge to achieve an on-resistance of the same order as GaN HEMTs. One approach is to distribute the total carriers in multiple parallel channels and modulate these parallel channels independently. A Mg-doped GaN/AlGaN superlattice (SL) is one way to get multiple parallel hole channels. Using MOCVD grown GaN/AlGaN superlattice, FinFET devices were fabricated and characterized. Initial devices employing MIS gate structure showed normally-on operation with >100 mA/mm. Next, Schottky gate structures were used to achieve normally-off operation. Finally, MOCVD regrown contacts around the fins led to devices with normally-off operation and >60 mA/mm.

Bio

Aditya Raj is a Ph.D. candidate in Department of Electrical & Computer Engineering at the University of California, Santa Barbara. His research focuses on III-Nitrides electronic device design, fabrication and characterization for high power and RF applications. He received his Electrical Engineering BT-MT dual degree from Indian Institute of Technology Kanpur, India in 2017.

Hosted by: Prof. Umesh Mishra

Submitted by: Aditya Raj <araj@ucsb.edu>