Historically, thermal annealing processes were most often performed using conventional resistively-heated tube furnaces. However, as device designs shrank late in the last century, it was found that the time at temperature profiles necessary for dopant activation and crystal damage repair in such approaches resulted in undesirable dopant diffusion. Since atom mobility within the silicon matrix is negligible at temperatures much below 900°C, temperature reduction was not an available option for solving this problem. As with thermal oxidation processes, most of this undesirable dopant migration occurred during the heat-up and cool-down phases in these processes. A typical furnace anneal process for dopant activation and crystal damage repair might require 30 minutes at 900°C. Under such conditions, dopant atoms, especially the small B atom, suffer excessive diffusion. Studies showed that dopant activation and crystal repair in the same substrate could be achieved with a 1050°C for 20 seconds (or less) without excessive dopant diffusion which led to the obvious problem resolution of rapid thermal annealing (RTA). As with rapid thermal oxidation, in RTA the silicon wafer is heated to high temperature in seconds by a bank of heat lamps. Cooling is also rapid since the thermal mass of the entire system is small.