High power lasers have been used in the semiconductor industry for many years, for applications such as wafer scribing, resistor trimming and the drilling of ceramics, where the clean removal of a specific amount of material is required; and for contact alloying, where permanent, relatively extensive chemical changes are sought [1.1]• Despite the mature development of these applications, however, lasers and electron beams have only recently been considered for the processing operations that are required during silicon device fabrication.
The earliest work with Q-switched lasers was performed by Russian workers [1.2-1.4], who showed that ion implanted silicon could be annealed successfully with laser pulses of sufficient energy and duration. The importance of this work was quickly appreciated by workers at several different laboratories in Europe [1.5-1.7] and the United States [1.8-1.10], and a large volume of published work has now appeared on the use of both Q-switched lasers and pulsed electron beams [1*11] for semiconductor processing. At the same time, the use of scanning cw laser and electron beams for annealing ion implanted silicon was being explored at Stanford [1.12-1.14], with a particular focus on its application to semiconductor device processing. More recently, both scanning and stationary incoherent light sources have been used to achieve annealing of ion implanted silicon with a wafer throughput that is compatible with the needs of the semiconductor industry.