An ohmic contact process for AlGaN/GaN structures using TiSi2 electrodes

Abstract

We report an Ohmic contact process using TiSi2 electrodes for contact metals on AlGaN/GaN structures. TiSi2 films have been formed by cyclic deposition of Ti and Si layers by sputtering and annealing. Cross-sectional TEM image of the sample annealed has revealed a formation of an interfacial layer above AlGaN layer, however, no intrusion of Ti or Si atoms has been observed at dislocation. Specific contact resistance on annealing time showed gradual reduction with longer time. Therefore, TiSi2 can be a candidate as a contact material for AlGaN/GaN structures independent to dislocation density of epiwafers.