Low-Frequency Noise Investigation of GaN/AlGaN Metal-Oxide-Semiconductor High-Electron-Mobility Field-Effect Transistor With Different Gate Length and Orientation

In this article, GaN/AlGaN metal–oxide–semiconductor high-electron-mobility field-effect transistors (MOSHEMTs) fabricated on high-resistivity Si (111) substrates have been evaluated using low-frequency (LF) noise measurement. The noise power spectral density (PSD) of devices with different lengths and channel orientations has been characterized in linear operation. No noticeable differences in the electrical and noise PSD characteristics have been observed between the GaN [ $1\overline {1}00$ ] and [ $11\overline {2}0$ ] channel orientations. While most devices are dominated by 1/ ${f}$ noise, originating from number fluctuations, for long devices ( ${L} \ge 1.1~\mu \text{m}$ ), additional generation–recombination (GR) noise has been observed, originating from traps in the GaN layer.