MICROWAVE-INDUCED LOW-TEMPERATURE CRYSTALLIZATION OF AMORPHOUS-SILICON THIN-FILMS

Microwave heating was utilized for solid phase crystallization of amor phous silicon films. The amorphous silicon thin films were deposited i n the temperature range of 100-400 degrees C by plasma enhanced chemic al vapor deposition and annealed by microwave healing at 550 degrees C in nitrogen. Microwave beating lowered the annealing temperature and reduced the annealing time for complete crystallization. For example, the a-Si film deposited at 400 degrees C was fully crystallized in 3 h at 550 degrees C. On microwave heating. the hydrogen in the amorphous films diffused out very quickly, but there was no change in structura l disorder following hydrogen evolution. The lower temperature crystal lization of a Si films compared to conventional furnace annealing is d ue to the interaction between microwave and silicon atoms. The grain s ize of the crystallized silicon films was in the range of 0.55-0.78 mu m, depending on the deposition temperature. These grain sizes are not so small compared to those of Si films crystallized by conventional f urnace heating, while the crystallization time is much shorter. (C) 19 97 American Institute of Physics.