Fabrication of poly 3C-SiC thin film diodes for extreme environment applications

Polycrystalline (poly) 3C-SiC thin films were deposited onto oxidized Si wafers by APCVD using HMDS as a precursor. In this work, the optimized growth temperature and HMDS flow rate were 1,100degC and 8 sccm, respectively. A Schottky diode with a Au/poly 3C-SiC/Si(n-type) structure was fabricated and its threshold voltage (V_d), breakdown voltage, thickness of depletion layer, and doping concentration (N_D) values were measured as 0.84 V, over 140 V, 61 nm, and 2.7 times 10¹⁹ cm³, respectively. To produce good ohmic contact, Al/3C-SiC were annealed at 300, 400, and 500degC for 30 min under a vacuum of 5.0 times 10^-6 Torr. The obtained p-n junction diode fabricated by poly 3C-SiC had similar characteristics to a single 3C-SiC p-n junction diode.