Study of a-Si crystallization dependence on power and irradiation time using a CW green laser

Abstract

An advantage of laser crystallization over conventional heating methods is its ability to limit rapid heating and cooling to thin surface layers. Laser energy is used to heat the a-Si thin film to change the microstructure to poly-Si.Thin film samples of a-Si were irradiated with a CW-green laser source. Laser irradiated spots were produced by using different laser powers and irradiation times.These parameters are identified as key variables in the crystallization process. The power threshold for crystallization is reduced as the irradiation time is increased. When this threshold is reached the crystalline fraction increases lineally with power for each irradiation time.The experimental results are analysed with the aid of a numerical thermal model and the presence of two crystallization mechanisms are observed: one due to melting and the other due to solid phase transformation.

Enabling n-type polycrystalline Ge junctionless FinFET of low thermal budget by in situ doping of channel and visible pulsed laser annealing

“…The accumulation of phosphorus atoms near the poly-Ge surface mainly results from the laser-generated thermal gradient. 18) The SRP analysis gives the electrically active electron concentration in an n-type poly-Ge film. A low electron concentration of 2 × 10 18 cm −3 near the surface and a high electron concentration of 2 × 10 19 cm −3 near the bottom region of the poly-Ge film were obtained.…”