Short time annealing has recently become of interest in silicon processing as a technique to activate ion implanted dopants, remove defects, and regrow amorphized silicon, with minimal diffusion of the dopant atoms. Short time annealing is carried out using a variety of energy sources ranging from arc lamps and resistance heaters with heating times of a few tens of seconds, to laser, electron, and ion sources with heating times of a few milliseconds down to nanoseconds. The annealing processes are grouped according to the time durations of the anneal and with reference to the thermal response time of the silicon. These are designated as adiabatic for < 10-6 sec; thermal flux for 10-6-10-2 sec, and isothermal for > 10-2 sec. Processes in the adiabatic regime result in surface melting, regrowth of silicon free of extended defects, and complete dopant activation. However, the dopant diffuses throughout the melt zone. In the thermal flux and isothermal annealing regimes the dopant can be activated, and amorphous silicon regrown epitaxially with little dopant diffusion. In the limited results reported to date, the complete removal of extended defects has not been achieved. Further investigation may yield new results in extended defect removal. © 1983, The Electrochemical Society, Inc. All rights reserved.