Effects of light pulse duration on excimer-laser crystallization characteristics of silicon thin films

The waveform of an excimer-laser light pulse has been varied using two laser systems with a delayed trigger. The effects of the pulse duration on the physical properties of crystallized silicon thin films were studied. Fromthe results that threshold energies for crystallization, amorphization and ablation increased in proportion to thesquare root of light pulse duration, their critical temperatures were estimated to be 1000°C, 1800°C and 2700°C, respectively. It was found that the critical temperature for i-crystallzation is changed from about 2600° C for athin film under short pulse duration conditions to 1800°C for a thick film under long pulse duration conditions.The long pulse is effective, but not drastic, in improving the poly-crystallized silicon film quality.