Preparation Of Amourphous Silicon Thin Films And Continuous-wave Laser Crystallization

The invention of solar cells plays an important role on tackling energy crisis and environmentalpollution. among all kinds of solar cells, silicon-based solar cells hold a dominant position for the reasonthat the raw material silicon is semiconductor material and rich in content. Its development has experiencedsingle crystalline silicon solar cell, polycrystalline silicon solar cell and amorphous silicon thin film solarcell. compared with the former ones, amorphous silicon thin film solar cell can save a large amount ofsilicon material, it has gained adequate development and has a mature industrial technology,However, amorphous thin film silicon solar cell has two severe defects: the first is that the lowutilization of long-wave optical band affects the efficiency of battery; the second is that "Steabler-Wronskieffect"-the efficiency of battery decreases heavily under long use of battery-exists. people has come upwith many ways to overcome these shortcomings, one attracted is replacing amorphous silicon thin filmwith polycrystalline silicon thin film, because it can not only absorb the light of long wave band, but alsogreatly overcome "Steabler-Wronski effect".polycrystalline silicon thin film has been recognized as a kindof ideal photovoltaic material.There are many ways to prepare polycrystalline silicon thin films, it mainly includes direct depositionmethod and secondary crystallization method, the former includes vapor deposition method and liquidphase epitaxial method,the latter includes high temperature furnace annealing, rapid thermal annealing,metal induced crystallization and laser crystallization method. the principle of laser crystallization methodis using the high energy of laser to instantly proceed annealing crystallization on the surface of thin filmwithout harm to substrate at the same time, so it can adopt cheap material such as glass and ceram, the costof battery production will consequentlybe reduced greatly.In the process of laser crystallization, there are two factors to measure the crystallization effect: one isthe crystallization rate,the higher the better; another is the uniformity of crystallization, the more uniformthe better. in this paper, amorphous silicon thin film is prepared firstly and then crystallized by laser, westudied the effect of various paraments on the process of preparation of polycrystalline slicon thin films. thespecific work contents are as follows: 1. Amorphous silcon thin fims are prepared by D.C. magnetron sputtering, the effect of sputteringpower and Argon pressure on the deposition rate are studied.2. With continuous Ar+Kr+laser as the light source,we study the effect of laser power density on thecrystallization of amorphous silicon thin films.3.The effect of laser irradiation time on the crystallization of amorphous silicon thin films are studied.4.The effect of substrates on the crystallization of amorphous silicon thin films are studied.5.The effect of wavelength on the crystallization of amorphous silicon thin films are studied.6.Change the laser scanning way and observe the corresponding crystallizaion effect...