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A preliminary study on the solid-phase crystallization in the porous silicon, crystalline silicon thin film was prepared .

Author: LiHongJu
Tutor: ZhangYuXiang
School: Zhengzhou University
Course: Condensed Matter Physics
Keywords: Polysilicon thin film Electrochemical corrosion Porous silicon PECVD Solid-phase crystallization
CLC: O484
Type: Master's thesis
Year: 2007
Downloads: 209
Quote: 0
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Abstract

In oil and gas prices continue to rise, renewable energy (especially solar) has become the focus of the countries major research group to study. With the depth study of the third generation solar cells - thin-film solar cell, it is necessary to improve the photovoltaic conversion efficiency of the polycrystalline silicon thin film solar cell, the preparation of the high quality of the polysilicon film is essentially a way to solve the problem. This article in the preparation of high-quality polycrystalline silicon thin film has done some exploratory work, film transfer technology for the development of low-cost crystalline silicon thin film solar cells provide a new way to take advantage of the low intensity of the middle layer (high porosity of the porous silicon layer) The method, in between the substrate and the thin film solar cell, after Daizhi good thin film solar cells by mechanical stress of the thin film solar cell substrate separation, which is a relatively new class of solar cell fabrication method. This thesis it is to prepare a polycrystalline silicon thin film solar cell material excellent for the purpose of, first electrochemical etching method for the preparation of porous silicon, and then depositing a silicon film on the porous silicon and the secondary crystallization. First, the experimental electrochemical corrosion prepared porous silicon to study the corrosion current, etching time and HF acid concentration, temperature, porosity, and porous silicon surface morphology of the influencing factors, further study of porous silicon peel . The study found that: (1) a porosity of the porous silicon with the corrosion current density increases, the extension of the etching time, temperature rise, the HF concentration decreases with increasing. But is valid only within a certain range, that is to ensure that no electro-polishing; (2) the resistor has a great influence on the porous silicon, the large resistivity not easy to form the porous silicon layer, only the resistivity is very hours to form a homogeneous porous silicon layer; (3) due to the enormous capillary stress generated by the liquid in the pores of the porous silicon in the NATURAL gasification during the evaporation process, fresh samples of porous silicon surface substantially dry in the air after the occurrence of cracks; (4) to increase the porous silicon the corrosion current density, it is greater than the critical current of the formation of porous silicon, electrochemical polishing, successful peeling of the porous silicon layer, porous silicon layer in the near UV - visible - near infrared entire band are very low reflectance. Secondly, the plasma-assisted chemical vapor deposition (PECVD) method on the porous silicon substrate was prepared amorphous silicon film. The subsequent heat treatment for recrystallization of the amorphous silicon thin film, with the solid-phase crystallization method for the preparation of polycrystalline silicon thin film on the amorphous silicon thin film on the porous silicon. The substrate, annealing, temperature, doping, time on the thin film crystallization. SYSTEM silicon film before and after the heat treatment, the plasma chemical vapor deposition (PECVD) by laser Raman spectroscopy and X-ray diffraction (XRD) analysis. Found that: (1) the effect of the crystallization of a silicon film on the porous silicon than quartz good; (2) crystallization of crystallization than the samples of the conventional thermal annealing rapid thermal annealing; (3) each of the solid-phase crystallization temperature the best time corresponds to a crystallization; (4) increased when the solid-phase crystallization temperature can reduce the crystallization time; (5) a thin film of boron-doped than the intrinsic film crystallization effect, is conducive to the epitaxial growth of the film; (6) at the time of annealing, the silicon film, H escape formed Alice skin, reducing the quality of the film.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Thin Film Physics
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