Controlled thermal kinetics in RTP
Ultra-shallow junction formation is one of the most exciting new challenges for RTP process engineers and vendors. In many cases, reaction rat limited and diffusion limited processes are to be promoted or suppressed in a complementary manner. In the case of reaction rate limited processes, a short time “flash” annealing at higher temperatures is often more advantageous than the conventional temperature-time functions for 10–60 s with linear ramps. We have to optimize two phenomena simultaneously: the most effective dopant activation and defect removal without dopant loss. At the same time dopant profile redistribution is to be limited as much as possible. Beside the thermal kinetics of implant annealing, a proper surface control is also very important. Surface etching due to SiO formation with subsequent implant evaporation is as detrimental as SiO2 growth with subsequent implant segregation. The importance and possibilities of “controlled thermal kinetics” and “limited concentration” processing mode are shown in some RTA experiments.