Field-plate Terminated Pt/n-4H-SiC SBD Using Thermal SiO2 and Sputter Deposited AlN Dielectric Stack

Silicon dioxide (SiO2), 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 mu m to 1.3 mu m have been deposited on 4H-SiC n-type samples with a 10 mu m thick epilayer doped with nitrogen to a concentration of 1.7-3.5x10(15)/cm(3). The V-B of the diodes was found to improve to as much as 1500 V at t(AlN) = 0.8 mu m, 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.