High voltage operation of field‐plated AlInN HEMTs

Abstract

Abstract In this paper, we report for the first time, high voltage operations of field plated Al 1–x In x N (x≈0.18) HEMTs. The epilayer structure of our devices consisted of AlInN/GaN HEMT structure with and without AlN cap layer. 1.25 μm gate‐length AlInN/GaN HEMT devices were then fabricated with 2 μm source‐gate distance using our baseline fabrication process. The gate‐drain spacing were varied from 6 (baseline) to 12 μm. The devices were field‐plated to analyze the breakdown voltage. The maximum drain current density in devices grown on sapphire substrates was around 1.2 A/mm (at a +3 V gate bias). Maximum transconductance was around 370 mS/mm. The insulating AlN cap layer, combined with the field‐plated gate design had proved to substantially improve the devices OFF‐state breakdown voltage. The measured breakdown voltage was as high as 350‐400 V. The results presented highlights the potentials of AlInN‐based devices for the high‐voltage and energy‐efficient power‐electronics applications (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)