Annealing, an important step in semiconductor materials processing, can be accomplished by rapidly heating the silicon wafer to a high temperature for a short period of time. The schematic shows a method involv- ing the use of a hot plate operating at an elevated tem- perature Th. The wafer, initially at a temperature of Tw,i, is suddenly  positioned  at  a  gap  separation  distance L from the hot plate. The purpose of the analysis is to compare the heat fluxes by conduction through the gas within the gap and by radiation exchange between the hot plate and the cool wafer. The initial time rate of change in the temperature of the wafer, (dTw /dt)i, is also of interest. Approximating the surfaces of the hot  plate and the wafer as blackbodies and assuming their diameter transfer modes and the effect of the gap distance on the heating process. Under what conditions could a wafer be heated to 900°C in less than 10 s?