Structural Characteristics Study of Indium Diffusion in Silicon Using a Pulsed Nd:YAG Laser

Abstract

In the current study, a pulsed Nd:YAG laser was employed to induce indium diffusion in silicon by laser irradiation of a thin indium film deposited on silicon. The work was aimed to study the structural characteristics changes of the irradiated region resulting from varying laser pulse energy within the range (0.25-0.53)J and varying silicon temperature from 300K to 373K during laser irradiation. Optical and scanning electron microscopes were used for the surface topography study of the samples. The study showed formation of linear cracks, protrusions and craters depending on the laser energy used. The indium diffusion depth within the silicon was determined using an energy dispersive spectra (EDS). This was done when illuminating at the laser melting threshold at substrate temperature of 373K and when illuminating at higher laser energy and substrate at room temperature (300K). the diffusion depth increased and the impurity concentration at the surface decreased as laser energy got higher. Higher substrate temperature helped increasing the impurity concentration at the surface.