Crystallization of Amorphous LPCVD Silicon Films and Application to Bipolar and Thin Film Transistors

ABSTRACTWe studied the crystallization of LPCVD amorphous silicon films by TEM and found that the grain size of crystallized films depends upon the deposition and annealing conditions. The grain size increases as the deposition and/or the annealing temperature decreases. We also investigated the application of crystallized films in the fabrication of polysilicon emitter bipolar transistors and thin film transistors. The performance of bipolar transistors was found to have a small dependence on the grain size. In contrast, the performance of thin film transistors was strongly dependent upon the grain size.