Comparison of the stress between rapid thermal annealed and excimer laser annealed polycrystalline silicon thin films

Abstract

Characteristics of polycrystalline silicon films with large substrate such as 50 mm x 50 mm, crystallized by using furnace annealing (FA), multi-step rapid thermal annealing (MSRTA) and excimer laser annealing (ELA) methods, have been investigated. In order to characterize the residual stress in crystalline silicon on coming 7059 glass, polarized Raman spectroscopy were measured for those various annealing methods and at various substrate temperatures. We observed that the polycrystalline Si films, crystallized by ELA, have a high crystalline volume fraction, residual stress and equiaxial crystal growth. On the other hand, silicon films crystallized by FA and MSRTA have a low compressive stress and dendritic structure, which are due to thermal relaxation. These Si films have a broad hump around 480 cm(-1) which indicates the existence of amorphous phase silicon. The magnitudes of stresses of FA and MSRTA are 4.07 x 10(9) and 4.46 x 10(9) dyne cm(-2), respectively and the magnitude stress of laser annealing decreases from 1.35 x 10(10) to 8.58 x 10(9) dyne cm(-2) with increasing the substrate temperature from room temperature to 400 degrees C. (C) 1998 Elsevier Science Ltd.