激发频率对纳米晶硅薄膜晶化特性的影响

Effect of Excitation Frequencies on Crystalline Properties of Nanocrystalline Silicon Thin Films

为制备高质量的纳米晶硅薄膜,采用等离子体化学气相沉积方法,以硅烷、高纯氢为源气体,氢稀释率保持在98%,衬底温度200℃,反应气压100 Pa,沉积时间60 min,在射频频率分别为13.56、54.24 MHz下合成了纳米晶硅薄膜。利用Raman光谱和X射线衍射技术分析了样品,结果表明,高激发频率可促进薄膜从非晶硅到纳米晶硅的转化,有利于提高薄膜的晶化率,且晶粒具有各种晶体取向,没有出现择优生长。当激发频率从13.56 MHz升高到54.24 MHz时,晶化率相应从9%提高到72%。

In order to synthesize high quality nanocrystalline silicon thin films,the PECVD（plasma enhanced chemical vapor deposition） technique was adopted under the preparing conditions of high hydrogen dilution ratio（98%）,low substrate temperature（200 ℃）,high deposition pressure（100 Pa） and different excitation frequency（13.56 MHz or 54.24 MHz）.The microstructure of the deposited films at different excitation frequencies were studied by the Raman spectrum and X-ray diffraction technique.The results show that high excitation frequencies can accelerate the phase transformation from amorphous to nanocrystalline and increase the crystalline fraction of the films.With the excitation frequency increasing from 13.56 MHz to 54.24 MHz,the crystalline fraction of the films increases from 9% to 72%.