Microwave heating was utilized for solid phase crystallization of amorphous silicon films. The amorphous silicon thin films were deposited in the temperature range of 100–400 °C by plasma enhanced chemical vapor deposition and annealed by microwave heating at 550 °C in nitrogen. Microwave heating lowered the annealing temperature and reduced the annealing time for complete crystallization. For example, thea-Si film deposited at 400 °C was fully crystallized in 3 h at 550 °C. On microwave heating, the hydrogen in the amorphous films diffused out very quickly, but there was no change in structural disorder following hydrogen evolution. The lower temperature crystallization ofa-Si films compared to conventional furnace annealing is due to the interaction between microwave and silicon atoms. The grain size of the crystallized silicon films was in the range of 0.55–0.78&mgr;m, depending on the deposition temperature. These grain sizes are not so small compared to those of Si films crystallized by conventional furnace heating, while the crystallization time is much shorter. ©1997 American Institute of Physics.