PECVD生长nc-Si:H膜的掺杂特性研究

A Study of Doping Properties on Nanometer Silicon Thin Films Growed by PECVD

采用常规ＰＥＣＶＤ工艺，以高Ｈ２ 稀释的ＳｉＨ４ 作为反应气体源，以ＰＨ３ 作为Ｐ原子的掺杂剂，在Ｐ型（１００） 单晶硅（ｃ－ Ｓｉ） 衬底上，成功地生长了掺Ｐ的纳米硅膜（ｎｃ－ Ｓｉ（Ｐ）：Ｈ） 膜。通过对膜层结构的Ｒａｍａｎ 谱分析和高分辨率电子显微镜（ＨＲＥＭ） 观测指出：与本征ｎｃ－ Ｓｉ：Ｈ 膜相比，ｎｃ－ Ｓｉ（Ｐ）：Ｈ 膜中的Ｓｉ 微晶粒尺寸更小（～３ ｎｍ） ，其排布更有秩序，呈现出类自组织生长的一些特点。膜层电学特性的研究证实，ｎｃ－ Ｓｉ（Ｐ）：Ｈ 膜具有比本征ｎｃ－ Ｓｉ：Ｈ 膜约高两个数量级的电导率，其σ值可高达１０－ １ ～１０１ Ω－１ｃｍ －１ 。这种高电导率来源于ｎｃ－ Ｓｉ（Ｐ）： Ｈ 膜中有效电子浓度ｎｅ 的增加、Ｓｉ 微晶粒尺寸ｄ 的减小和电导激活能ΔＥ的降低。

Phosphor-doped nanometer crystalline silicon(nc-Si(P):H) films are successfully grown on the p-type(100) oriented crystal silicon(c-Si) substrate by conventional PECVD. The films is obtained using high H2 dilute SiH4 as a reaction gas soure and using PH3 as a doping gas soure of phosphor atoms. The film structures are studied by using Raman spectrum and high resolution electron microscopy(HREM). Si microcrystalline size in nc-Si(P):H films is more small (～ 3nm) and is more order in arrangements by comparasion with intrinsic nc-Si:H films, have some characteristics of like-self organization growth. The study of its electrical properties pointed out that nc-Si(P):H films make two order of magnitude improvement in conductivity by comparision with intrinsic nc-Si:H films, the values are as high as 10-1～101 Ω-1cm-1. Thus high conductivity is results in increase of effective electron concentrantions in nc-Si(P):H films, decrease of Si micocrystalline size and reduction of conductive active energy.