OHMIC CONTACTS TO III-V-COMPOUND SEMICONDUCTORS

Scaling of III-V semiconductor devices to submicrometre dimensions imposes more stringent requirements on electrical and metallurgical characteristics of ohmic contacts. In this paper, we discuss key technological issues of advanced ohmic contact technology for III-V semiconductors. Recent progress in the determination of the contact microstructure is overviewed and the mechanism of formation of low resistance metal-semiconductor junctions is discussed. The kinetics of reaction at the metal-semiconductor interface and the structural factors that govern its electrical behaviour are analysed. Results on the optimization of conventional gold-based ohmic contacts together with recent achievements in the technology of non-alloyed contacts are presented.