Phosphorus Dopant Diffusion, Activation, and Annealing. Using Infrared Laser for Synthesis of n-Type Silicon Thin Film

Abstract

Thin film of oriented crystalline intrinsic poly silicon films were grown on alkali free borosilicate glass substrate using hot wire chemical vapour deposition technique. A layer as a source of phosphorus dopant on top of intrinsic poly silicon films were introduced in two different approaches, i) spin on one micron thick phosphorus dopant and ii) phosphorus ion implantation. The possibility of dopant diffusion, activation and annealing were investigated using the irradiation of 1064 nm wavelength infrared laser. The annealing is performed under various conditions. The laser power and scan speed was varied to ensure the suitable laser annealing condition. Resistivity measurement was carried out to validate the laser annealing process. Several characterization techniques such as, scanning electron microscopy, high resolution x-ray diffraction, photoluminescence spectroscopy and confocal Raman spectroscopy measurement have been used for structural investigation. Optical transmission spectrum had been used for determining optical characteristics of the film. The electrical measurement shows that the phosphorous doped n-type poly silicon films are suitable as an emitter layer in photovoltaic device.