We report synthesis of highly (220) oriented and passivated polycrystalline silicon films on glass by using Hot Wire Chemical Vapor Deposition (HWCVD) without using any buffer. Oriented growth is initiated by deposition at 400·C using dilute mixture of Silane(SiH4) and Hydrogen(H2) , a condition which favours growth of (220) oriented nuclei. After that most of the growth is done at 600-700·C using less dilute SiH4 + H2• Films are passivated by in-situ soak in atomic hydrogen between 400-300·C. At 300K, films have dark conductivity about 10.6 (n cm)"l. Illumination with a white light LED of flux about 1 sun increases the conductivity to 1-2x 10.5 (n-cm)"l. In addition photoluminescence emission is observed both at 18 K and at 300K. These features suggest films are well passivated.

Boron-doped polycrystalline silicon film was synthesized using hot wire chemical vapor deposition technique for possible application in photonics devices. To investigate the effect of substrate, we considered Si/SiO2, glass/ITO/TiO2, Al2O3, and nickel tungsten alloy strip for the growth of polycrystalline silicon films. Scanning electron microscopy, optical reflectance, optical transmittance, X-ray diffraction, and I-V measurements were used to characterize the silicon films. The resistivity of the film was 1.3 × 10−2 Ω-cm for the polycrystalline silicon film, which was suitable for using as a window layer in a solar cell. These films have potential uses in making photodiode and photosensing devices.

The parameters of crystalline semiconductor such as types of semiconductor, uniformity of impurity concentration of doped wafer, majority charge carrier concentration, sheet resistivity of doped wafer surface play an important role in solar cell fabrication process during emitter diffusion, that is the most critical step. In this paper, we have used a low cost in house made hot probe measurement setup. A hot plate was used to heat up the wafer up to 100°C. Two k-type thermocouples were placed simultaneously in contact with the hot and cold surface of the wafer to measure the temperature in situ for both hot and cold probe. We have used two copper probes with a voltmeter connected to measure the potential difference (thermoelectric voltage) between two probes for various temperatures up to 100°C with an interval of 10°C. We have taken measurement for commercial silicon wafer (thickness 200 µm) and one side polished 4 inch diameter Si wafer (thickness 660 µm) to determine the wafer type (n-type or p-type). We also calculated thermopower or Seebeck coefficient from the voltage vs. time curve, that is constant for particular substrate. As a process monitoring tool for solar cell fabrication process, after n-type diffusion using POCl3 on p-type silicon wafer of thickness 200 µm, we have done wafer mapping that gives us the information of doping uniformity over the whole surface of wafer both front and back side

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The gap between laboratory scale and commercial silicon solar cells is wider, as many processes are not being practiced in commercialization. In this work, we have investigated the silicon solar cell fabrication process followed by industries and proposed a simplified process. The fabrication process for the emitter layer, 100 nm thin film anti-reflection coating and wet oxide passivation in a single chamber diffusion furnace on 200 micron p-type mono crystalline silicon wafer was followed. The diffusion process was carried out in an atmospheric furnace using phosphorus oxychloride as dopant source, oxygen for anti-reflection coating and wet oxide surface passivation. Topographical, optical and electrical characterization were conducted to understand the properties of the above layers for application in solar cell fabrication. The reflectivity and average sheet resistivity data of the diffused wafer is in the range those published in literature. Following the procedure, number of process steps, instrument and cost of commercial solar cell fabrication can be optimized.