Characteristics of 21H-SiC Thin Film-Based Schottky Barrier Diodes Using TiN Contacts

Abstract

The fabrication of Schottky barrier diodes based on thin films of 21H polytype of SiC is reported. The films were deposited using a single composite target of Si and graphite by magnetron sputtering. The formation of the 21H polytype of SiC was confirmed by x-ray diffraction. The devices were fabricated on single-crystal Si substrates, and electrical properties with TiN and Au/TiN as top lateral contacts were investigated. The rectifying nature, temperature (in the range 300–423 K), and top electrode work function dependence of Schottky parameters were investigated. The room-temperature turn-on voltages for the TiN and Au/TiN top contacts were 8.9 V and 12.8 V, respectively. The ideality factor decreased while the barrier height increased with an increase in temperature. The barrier height for different temperatures was in the range of 1.16–0.82 eV and 0.9–0.77 eV for TiN and Au/TiN interfaces with SiC, respectively. The presence of TiCxNy on the surface of the TiN-SiC-Si-Au device at high temperatures observed using Raman spectroscopy revealed the inhomogeneity due to variation in local interfacial structure. It was demonstrated that the 21H-SiC-based thin film Schottky barrier diodes are a promising alternative for many applications.