Crystallization of Amorphous Silicon and Dopant Activation using Xenon Flash-Lamp Annealing (FLA)

Abstract

Flash-lamp annealing (FLA) has been investigated for the crystallization of a 60 nm amorphous silicon (a-Si) layer deposited by PECVD on display glass. Input factors to the FLA system included lamp intensity and pulse duration. Conditions required for crystallization included use of a 100 nm SiO₂ capping layer, and substrate heating resulting in a surface temperature ∼ 460 °C. An irradiance threshold of ∼ 20 kW/cm² was established, with successful crystallization achieved at a radiant exposure of 5 J/cm², as verified using variable angle spectroscopic ellipsometry (VASE) and Raman spectroscopy. Nickel-enhanced crystallization (NEC) using FLA was also investigated, with results suggesting an increase in crystalline volume. Different combinations of furnace annealing and FLA were studied for crystallization and activation of samples implanted with boron and phosphorus. Boron activation demonstrated a favorable response to FLA, achieving a resistivity ρ < 0.01 Ω•cm. Phosphorus activation by FLA resulted in a resistivity ρ ∼ 0.03 Ω•cm.