AlGaN/GaN Superlattice‐Based p‐Type Field‐Effect Transistor with Tetramethylammonium Hydroxide Treatment

Abstract

To realize the full spectrum of advantages that the III‐nitride materials system offers, the demonstration of p‐channel III‐nitride‐based devices is valuable. The first p‐type field‐effect transistor (pFET) based on an AlGaN/GaN superlattice (SL), grown using metal–organic chemical vapor deposition (MOCVD), is reported. Magnesium is used as the p‐type dopant. A sheet resistance of 11.6 kΩ □ −1 and a contact resistance of 14.9 Ω mm are determined using transmission line measurements (TLMs) for Mg doping of 1.5 × 10 19 cm −3 . Mobilities in the range of 7–10 cm 2 (V s) −1 and a total sheet charge density in the range of 1 × 10 13 –6 × 10 13 cm −2 are measured using room temperature Hall effect measurements. Without tetramethylammonium hydroxide (TMAH) treatment, the fabricated pFETs have a maximum drain‐source current ( I DS ) of 3 mA mm −1 and an on‐resistance ( R ON ) of 3.48 kΩ mm and do not turn off completely. With TMAH treatment during fabrication, a maximum I DS of 4.5 mA mm −1 , R ON of 2.2 kΩ mm, and five orders of current modulation are demonstrated.