A Planar Distributed Channel AlGaN/GaN HEMT Technology

Abstract

This brief presents AlGaN/GaN high electron mobility transistor (HEMT) devices with improved thermal and dc current–voltage ( ${I}$ – ${V}$ ) performance using a novel method of obtaining a distributed channel device, i.e., the total semiconductor area between the ohmic contacts comprise conducting and nonconducting regions. A novel oxygen (O2) plasma treatment technique is used to realize the inactive or nonconducting regions. Multifinger devices with 1-mm gate periphery exhibit extremely low gate leakage currents below $0.2~\mu \text{A}$ /mm at a gate voltage of −20 V and an increase in the saturated output current by 14% at 20-V drain voltage. Moreover, performed dc ${I}$ – ${V}$ measurements at various ambient temperatures show that the proposed method not only increases the saturated output currents by over 10% for ${1} \times {100}\,\,\mu \text{m}^{{2}}$ gate devices but also significantly reduces their knee walkout voltage from 6 to 3 V at 300 K. These results show that this device design approach can exploit further the potential of the GaN material system for transistor applications.