ON-LINE DETERMINATION OF AVERAGE GRAIN SIZE OF POLYCRYSTALLINE SILICON FROM MELT DURATION OF MOLTEN SILICON

We demonstrate a method of on-line determination of the average grain size of polycrystalline silicon (poly-Si) deduced from the melt duration of molten silicon during the phase transformation using an insitu optical measurement system. Optical measurements revealed that the entire phase transformation processes are melting, nucleation, and resolidification. The average grain size of poly-Si can be directly deduced from the melt duration of molten Si under a thickness uniformity of precursor a-Si thin films below +/- 5%, a pulse-to-pulse variation in the excimer-laser-beam energy below 2% (standard deviation), and a laser-beam spatial homogeneity below 2.5%.