Field-plate Terminated Pt- 4H-SiC SBD Using Thermal SiO_2 and Sputter Deposited AlN Dielectric Stack

摘要

Silicon dioxide (SiO_2), one of the commonly used dielectrics for field plate terminated 4H-SiC devices suffers from high electric field and premature breakdown due to its low dielectric constant (k). This problem can be addressed by using high-k dielectrics such as AlN that will reduce the field and improve the breakdown voltage (V_B). Sputter deposited amorphous AlN films with a thickness (t_(AlN)) ranging from 0.05 μM to 1.3 μm have been deposited on 4H-SiC n-type samples with a 10 μm thick epilayer doped with nitrogen to a concentration of 1.7-3.5×10~(5)/cm~3 . The V_b of the diodes was found to improve to as much as 1500 V at t_(AlN) =0.8 μm, which is more than 2 times the V_B of unterminated structures which have a premature breakdown between 600-700 V due to field enhancement at the diode periphery.