Kinetics of laser-induced solid phase epitaxy in amorphous silicon films

Abstract

The kinetics of laser and furnace-induced solid phase epitaxial crystallization of As-implanted amorphous layers (∼0.16 μm) on Si (100) substrates was studied using a time-resolved optical reflectivity technique. Epitaxial rates from 10−10 to 0.2 cm/sec were measured over a temperature range from 750 to 1550 °K at two different As concentrations, ∼2×1019 cm−3 and ∼4×1019 cm−3. Temperatures achieved during cw-laser heating were calculated using a three-dimensional steady-state thermal analysis. The crystal growth rates are accurately described by the Arrhenius equation v = v0e−Ea/kT , with Ea dependent on the dopant concentration; Ea = 2.62 and 2.52 eV for the lower and the higher concentrations, respectively. Additionally, the rate measurements at high temperatures imply that the melt temperature of amorphous Si is greater than 1550 °K.