a-C:F薄膜结构与电学性能研究  

Microstructures and Electrical Properties of a-C:F Films Grown by Electron Cyclotron Resonance Chemical Vapor Deposition

作　　者：吴振宇[1] 杨银堂[1] 汪家友[1] 

机构地区：[1]西安电子科技大学微电子研究所

出　　处：《真空科学与技术学报》2006年第1期36-39,65,共5页Chinese Journal of Vacuum Science and Technology

基　　金：电子元器件可靠性物理及其应用技术国家级重点实验室项目(No.51433020205DZ01)

摘　　要：采用电子回旋共振等离子体化学气相沉积(ECR-CVD)方法,以C4F8和CH4为源气体,在不同气体流量比R(R=[CH4]/([CH4]+[C4F8]))条件下沉积氟化非晶碳(a-C:F)薄膜。用原子力显微镜(AFM)分析了薄膜的表面形貌。用柯西(Cauchy)模型和Levenberg-Marquardt非线性迭代算法分析了薄膜的椭圆光谱。用X光电子能谱(XPS)和傅里叶变换红外光谱(FTIR)技术分析了薄膜的化学成分。随着气体流量比R的增大a-C:F薄膜C-C键结构增多,薄膜C/F比增大。a-C:F薄膜的介电常数取决于电子极化并随R的增大而上升。a-C:F薄膜导电行为在低场强区域呈现欧姆特性,在高场强区域符合Poole-Frankel机制。随着C-C含量的增大,π价带态和π*导带态之间的带隙减小,电荷陷阱深度减小,陷阱中的电子在场增强热激发作用下更容易进入导带,导致薄膜漏电流增加。Fouorinated amorphous carbon （a-C： F） films were, prepared using electron cyclotron resonance chemical vapor deposition （ECR-CVD） by varying gas flow ratio R（R = [CH4]/（[CH4] ＋ [C4F8]））.Atomic force microscopy （AFM） was used to characterize film topology. A three-phase Cauchy model and a non-linear Levenberg-Marquardt regression algorithm were used to fit ellipsometry. X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy （FTIR） were used to study chemical composition. The results show that the C-C bonds and the C/F ratio in the deposited films increase with increasing gas flow ratio R .The dielectric constant of a-C： F films is composed mainly of electron polarization and increases with increasing R. The conduction shows Ohmic charactefistics at low electric fields. Poole-Frankel mechanism is applied to explain the conduction at high fields. The band gap between π band and π^＊ band,as well as the trap energy decreases with increasing C-C concentration, leading to increase of leakage current due to field-enhanced thermal excitation of trapped electrons into the conduction band.

关 键 词：A-C:F 电学性能 ECR-CVD 化学组分 

分 类 号：O484.4[理学—固体物理]