Vertical transprot properties of GaN schottky diodes grown by molecular beam epitaxy

摘要

Laterla and vettical electron transport parameters were investigated in lightly doped n-GaN films, grown by MBE. DIodes were fabricated by forming Schottky barriers on a n-GaN films using a meas-etched vertical geometry. Doping concentrations and barrier heights were determined, from C-V measurements, to be 8-9x10~(16) cm~(-3) and 0.95-1.0 eV respectively. Reverse saturation current densities were measured to be in the 1-10x10~(-9) A/cm~2 range. using the diffusion theory of Schottky barriers, vertical mobility values were determined to be 950 cm~2/V-s. lateral mobility in fims grown under similar conditions was determined by Hall effect measurements to be 150-200 cm~2/V-s. The significant increase in mobility for vertical transport is attributed to reduction in electron scattering by charged dislocations.