Defects limiting performance of devices fabricated on GaN/metal heterostructure

Ni Schottky barrier contacts were processed to characterize quality and suitability of GaN films grown on (111) face of titanium carbide metallic substrates for vertical device application. We found that defects such as voids (pores) in the GaN film strongly influence the optical and electrical properties of the epitaxial layers. Micro-Raman studies showed that these voids have a high concentration of free carriers. Schottky barrier contacts placed on the regions with high defect density are characterized by high leakage current. Barrier height of Schottky contacts containing smaller number of defects were typically around 0.72 eV .