GaN Vertical-Channel Junction Field-Effect Transistors With Regrown p-GaN by MOCVD

Abstract

We report an experimental demonstration of GaN-based vertical-channel junction field-effect transistors (VC-JFETs). A p-GaN regrowth by metalorganic chemical vapor deposition (MOCVD) and a subsequent self-planarization process were developed to fabricate the GaN VC-JFETs. Fin-like channel regions were patterned by electron beam lithography (EBL) and aligned to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${m}$ </tex-math></inline-formula> -plane or <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> -plane. The electrical properties of lateral and vertical p-n junctions were characterized to verify the effectiveness of the p-GaN regrowth. Both VC-JFETs with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${m}$ </tex-math></inline-formula> -plane and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> -plane channels show decent gate modulation. We further discussed important factors that may affect the device performance including interfacial impurities and nonuniform acceptor distribution. This work highlights the successful demonstration of GaN VC-JFETs and lateral p-n junctions by an etch-then-regrow process, providing valuable information and reference for the further development of GaN power electronics.