Pulsed laser ablation of silicon with low laser fluence in a low-pressure of ammonia ambient

Abstract

Silicon was ablated by 532 nm wavelength of Nd:YAG laser in ammonia gas ambient. The influence of laser fluence and gas ambient pressures between 1.33×10 1 to 1.33×10 −5 Pa on the deposited compound was studied by in situ X-ray photoelectron spectroscopy and transmission Fourier transform infrared spectroscopy techniques. The results indicate that the deposited compound is composed of nonstoichiometric silicon nitride (SiN x , x=0–0.84). It has been shown that the composition of nitrogen to silicon is sensitive to the laser fluence; it increases with decreasing laser fluence. However, the ammonia gas ambient in these low pressures range had no influence on the composition of the deposited compound. The reaction of the ablated silicon with low-pressure ambient ammonia is proposed to be occurred on the substrate.