Low-resistance Ohmic contacts for high-power GaN field-effect transistors obtained by selective area growth using plasma-assisted molecular beam epitaxy Available to Purchase

Selective area growth (SAG) has been demonstrated using plasma-assisted molecular beam epitaxy (PAMBE) resulting in vastly improved Ohmic contacts for GaN-based high-power field-effect transistors (FETs). A heavily doped $n-GaN$ layer was grown only in the Ohmic contact region and the resulting nonalloyed $Ti∕Al∕Ti∕Au$ metal contacts exhibited linear Ohmic behavior. Through rapid thermal annealing, very low specific contact resistivity $(1.8×10−8Ωcm2)$ was obtained at $850°C$⁠. Furthermore, contact resistances below $0.8Ωmm$ were obtained by annealing at a wide range of temperatures $(750–950°C)$⁠. GaN metal-semiconductor FETs were fabricated to investigate the effect of the PAMBE-SAG on device performance, producing great improvement in the dc characteristics.