ATOMIC-FORCE MICROSCOPY STUDIES OF POLYSILICON GROWTH DURING DEPOSITION ON SILICON

Atomic force microscopy has been extensively used to investigate polys ilicon deposited on silicon for times ranging from 10 s to 45 min. The temperature deposition was 620-degrees-C. Two different regimes have been singled out: one corresponding to isolated grain growth followed by another one which corresponds to coalescence growth. For short time s (from 10 s to 1 min) the number of grains remains constant and they grow without any interaction with each other; the grain radii increase following a t1/3 law. When polysilicon grains have grown to a size la rge enough for them to interact with each other, coalescence takes pla ce and the growth regime is modified; the grain number decreases follo wing a 1/t law. For this second growth regime the surface exhibits a s elf-similarity type of behavior from which a dynamic scale law can be deduced.