Temperature-dependent electrical characterization of high-voltage AlGaN/GaN-on-Si HEMTs with Schottky and ohmic drain contacts

Abstract

In this work we present results of electrical parameters characterization of high-voltage AlGaN/GaN high electron mobility transistors with ohmic and Schottky drain electrodes on silicon substrates. The use of Schottky-drain contacts improves breakdown voltage (VBR), which was VBR=900V for LGD=20μm in contrast to VBR=505V for ohmic-drain contacts. Both types of transistors exhibit drain current density of 500mA/mm and leakage current of 10μA/mm. Temperature-dependent characterization reveals a drain current density decrease with increasing temperature. The Schottky-drain HEMTs are characterized by lower increase of the Ron (ΔRon=250% at 200°C) in comparison to ohmic drain contacts (ΔRon=340% at 200°C) relative to the room temperature due to decrease of on-set voltage of Schottky-drain HEMTs.