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通过改变氢气对硅烷气体的稀释程度 ,并保持其他的沉积参量不变 ,用等离子体增强化学气相沉积 (PECVD)方法成功地制备出处于非晶 微晶相变过渡区域的硅薄膜样品 .测量了样品的室温光电导和暗电导 ,样品的光电性能优越 ,在 5 0mW·cm- 2 的白光照射下 ,光电导和暗电导的比值达到 10 6 .在室温下用微区喇曼谱研究了薄膜的微结构特性 ,用高斯函数对喇曼谱进行了拟合分析 .结果表明 ,在我们的样品制备条件下 ,当H2 和SiH4 的流量比R较小时 ,样品表现出典型的非晶硅薄膜的结构特性 ;随流量比R的增大 ,薄膜表现出两相结构 ,其中的微晶成分随氢稀释比的增大逐渐增多 ;用量子尺寸效应估算了两个高氢稀释样品 (R >5 0 )中微晶粒的平均尺寸大小为 2 4nm左右 ;样品的中程有序度随氢稀释程度的增加而增大
By changing the dilution of hydrogen gas to silane gas and keeping the other deposition parameters unchanged, the silicon thin film samples in the transition region of amorphous microcrystalline phase were successfully prepared by PECVD. The photoconductivity and dark conductance of the samples were excellent at room temperature. The ratio of photoconductivity and dark conductance was 106 at white light irradiation of 50 mW · cm-2. The Raman spectra of the films , The Gaussian function was used to fit the Raman spectra.The results show that under the conditions of our sample preparation, when the flow ratio R of H2 and SiH4 is small, the samples show typical amorphous silicon thin films With the increase of the flow rate ratio R, the film shows a two-phase structure, in which the crystallite composition gradually increases with the increase of the hydrogen dilution ratio. Two high-hydrogen diluted samples (R> 50 ) In the average size of microcrystalline grains is about 24nm; sample mid-range order degree increases with the increase of hydrogen dilution