Electrical and structural properties of poly-Si films grown by furnace and rapid thermal annealing of amorphous Si

In the present work, the effect of rapid thermal annealing (RTA) on the electrical and structural properties of poly-Si thin films, grown by the crystallization of a-Si films deposited by rapid thermal low-pressure chemical vapor deposition, has been studied. Structural and electrical results were obtained using atomic force microscopy, transmission electron microscopy, electron spin resonance, electrical resistivity, and Hall mobility techniques. The effects of the grain size, grain boundaries, and surface roughness on the electrical characteristics of poly-Si films have been investigated. Amorphous Si (a-Si) films crystallized by RTA at 850 degrees C for 45 s result in the formation of poly-Si with small grains, an electron spin density N-s=5.2 x 10(16) cm(-3), and a Hall mobility mu(H) = 30 cm(2) V-1 s(-1). A two-stage annealing, involving low-temperature annealing at 600 degrees C for 6 h, followed by RTA at 850 degrees C in five steps of 30 s each, results in the formation of poly-Si films with large grains free of in-grain defects, low surface roughness, and higher Hall mobility mu(H) = 43 cm(2) V-1 s(-1), characteristics rendering such poly-Si films suitable for the fabrication of good performance thin film transistors. (C) 1998 American Institute of Physics. [S0021-8979(98)03615-9].