A p-Type GaN MOSHFET on Si Substrates with Enhanced-Mode Operation and High-Temperature Stability

Abstract

This paper reports p-channel metal-oxide heterostructure field-effect transistors (MOSHFETs) based on p-GaN/GaN/Al_0.29Ga_0.71N heterostructures grown by metal-organic chemical vapor epitaxy (MOCVD) on Si substrates. The two-dimensional hole gas (2DHG) density in the p-GaN/GaN/Al_0.29Ga_0.71N heterostructures is 1.3×10¹³ cm^-2 and remains unchanged down to a temperature of 80 K. A reduction of the GaN channel thickness by dry etching renders the p-channel MOSHFET enhancement-mode (E-mode) with a negative threshold voltage (V_th). The E-mode p-channel MOSHFET realized by GaN (18 nm)/Al_0.29Ga_0.71N shows a threshold voltage V_th of -0.79 V, an on-current |I_ON| of 2.41 mA/mm, a low off-state drain-source current (|I_OFF|) of 2.66×10^-9 mA/mm and a low subthreshold swing (SS) of 116 mV/dec. Such ultralow |I_OFF| and SS indicates high-quality epitaxial material. The high-temperature operation capability of the p-MOSHFET is evaluated up to 200 °C.