Electrical contacts and degradation mechanisms

The proper choice of a metal for contact to a semiconductor (e.g. Si, GaAs, SiC, diamond at high temperatures) or oxide (piezoelectric substrate) is a major challenge, in particular for the design and fabrication of integrated circuits. As device dimensions in very large scale integration (VLSI) nowadays approach submicrometer scales only limited penetration of the metal into the semiconductor in the range of several nanometers can be accepted. An overview will be given regarding some basic materials issues for contact materials in particular considering the degradation at high temperatures.