Physics‐Based Simulation for Studying the Impact of Contact Resistance on DC and RF Characteristics of AlGaN/AlN/GaN HEMT

Abstract

AbstractFormation of a two‐dimensional electron gas in AlGaN/AlN/GaN heterostructures plays a vital role in high power and high frequency device technology. Such kinds of heterostructures are used for the fabrication of high electron mobility transistors (HEMTs). Ohmic contacts to AlGaN/AlN/GaN‐based heterostructures with low contact resistance and smooth surface are crucial in the development of high power, high frequency transistors in the GaN system. In the present study, physics‐based simulation of impact of ohmic contact resistance on DC and RF characteristics of AlGaN/AlN/GaN HEMT on 6H‐SiC substrate has been addressed for the first time. Samples A, B, and C of contact resistance 0.25, 0.27, and 0.59 Ω * mm, respectively, were fabricated with different process variations. By using measured contact resistance values, physics‐based simulation of 100‐nm gate length GaN HEMT was done, and corresponding device behavior was studied using TCAD. It has also been shown that simulated results for AlGaN/AlN/GaN heterostructure are closely matching with reported measured data.