EFFECTS OF GAS FLAME ANNEALING ON THE STRUCTURE OF POLY-SI FILMS

The effect of gas flame annealing on the structure of polycrystalline Si films was studied using transmission electron microscopy and electr on spin resonance. This annealing technique involved heating the sampl e surface to more than 1100 degrees C using hat gas flames with a scan rate of 1 mm/s and a heating rate of about 260 degrees C/min. Electro n microscopy images revealed that the secondary grain growth proceeded with increasing the number of annealing times (annealing frequency) a nd that the grain size for samples annealed at 1360 degrees C was more than 1 mu m whereas secondary grain growth was not significant for sa mples annealed at 1150 degrees C. Further, it was found that the spin density in the samples annealed at 1360 degrees C decreased from 1.5 X 10(18) cm(-3) to 3.8 X 10(17) cm(-3). It was concluded from the spin resonance results and the electron microscopy images that the secondar y grain growth consists of two processes, the initial structural rearr angement of the grain boundaries and the subsequent grain growth. (C) 1995 American Institute of Physics.