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 (VB). Sputter deposited amorphous AlN films with a thickness (tAl) 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 1.7–3.5×1015/cm3 . The VB of the diodes was found to improve to as much as 1500 V at tAl = 0.8 μm, which is more than 2 times the VB of unterminated structures which have a premature breakdown between 600-700 V due to field enhancement at the diode periphery.
Akira Suzuki, Hajime Okumura, Tsunenobu Kimoto, Takashi Fuyuki, Kenji Fukuda and Shin-ichi Nishizawa
A. Kumta et al., "Field-Plate Terminated Pt/n- 4H-SiC SBD Using Thermal SiO2 and Sputter Deposited AlN Dielectric Stack ", Materials Science Forum, Vols. 600-603, pp. 987-990, 2009