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

Thin film of oriented crystalline intrinsic polysilicon films were grown on alkali-free borosilicate glass substrate using hot-wire chemical-vapor-deposition (HWCVD) technique. A layer as a source of phosphorus dopant on top of intrinsic polysilicon films were introduced in two different approaches: (i) spinon one-micrometer-thick phosphorus dopant and (ii) phosphorus ion implantation. We investigate the possibility of dopant diffusion, activation, and annealing, using the irradiation of 1064 nm wavelength infrared laser. The annealing is performed under various conditions. The laser power and scan speed are varied to ensure the suitable laser annealing condition. We carry out resistivity measurements to validate the laser annealing process. For structural investigation, we use several characterization techniques, such as scanning electron microscopy, high-resolution X-ray diffraction, photoluminescence spectroscopy, and confocal Raman spectroscopy measurements. We use optical transmission spectra for determining optical characteristics of the film. The electrical measurement shows that the phosphorous-doped n-type polysilicon films are suitable as an emitter layer in photovoltaic device.