Novel RTA technique for large diameter GaAs wafers managing to minimize both dopant diffusion and slip formation

Abstract

Rapid thermal annealing (RTA) is useful for shallow channel device fabrication because of suppression of dopant diffusion. However, short RTA sequence easily causes slip formation due to thermal stress during the process, which is more serious in the case of larger diameter wafers. We investigated at what point slip generated during RTA by monitoring temperature distribution within a wafer and successfully suppress slip formation by introducing a waiting step in the cooling process while maintaining the high cooling rate and the abrupt doping profile.