腐蚀时间对多孔硅层形貌及多晶硅性能的影响
Effect of Corrosion Time on Porous Layer Morphology and Polycrystalline Silicon Properties
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摘要: 采用化学腐蚀方法在多晶硅表面制备多孔硅层, 通过外吸杂热处理方法进行除杂后对腐蚀不同时间后多孔硅层的形貌、多晶硅少子寿命和电阻率等进行了研究。结果表明: 随着腐蚀时间的延长, 形成的多孔硅层呈现不同的形貌, 多孔壁孔径逐渐变大, 少子寿命延长且电阻率增大; 腐蚀14 min后, 多孔硅层局部区域坍塌, 孔壁变薄; 腐蚀11 min时, 经850 ℃吸杂处理的多孔硅层少子寿命和电阻率达到峰值, 分别为0.98 μs和0.16 Ω·cm。Abstract: Porous silicon layer was prepared on the surface of polycrystalline silicon by chemical etching. The surface morphology, polycrystalline silicon minority carrier lifetime and resistivity of the porous silicon layers etched for different times were investigated after impurity removing by external gettering heat treatment. The results show that with the prolongation of etching time, the surface morphology of porous silicon layer was different, the pore diameter of the porous silicon got large gradually, the minority carrier lifetime and the resistivity were enhanced too. Some partial areas of porous silicon collapsed and the wall of holes turned thinner after etching for 14 min. The minority carrier lifetime and the resistivity of porous silicon reached 0.98 μs and 0.16 Ω·cm respectively after etching 11 min and gettering treatment at 850 ℃.