In-depth profiling of sputter-induced space-charge compensation in p-silicon Schottky barriers

The dc sputtering of gold on p-type silicon introduces sputter (damage) effects, which can be divided into surface effects and space-charge region effects. The space-charge region effects are investigated by capacitance profiling in combination with anodic oxide stripping of thin layers of silicon. In this way, it is possible to obtain a complete profile of sputter-induced electrically active states, not only at the end of the space-charge region, but up to the surface of the silicon. It is observed that donorlike states are capable of almost fully compensating the acceptor states over distances of one micrometer typically. Possible explanations for the origin of these states in terms of field-enhanced diffusion of species activated during the sputter process are discussed.