非晶氟化碳膜的制备与性能研究  

Preparation and Properties of Fluorinated Amorphous Carbon Films

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宽禁带半导体材料与器件教育部重点实验室,西安710071

出　　处：《微细加工技术》2005年第3期42-47,共6页Microfabrication 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资助项目(51433020205DZ01)

摘　　要：采用电子回旋共振等离子体化学气相沉积(ECR-CVD)的方法,以C4F8和CH4为源气体,在不同气体质量流量比R(R=m(CH4):m(CH4+C4F8))条件下制备了非晶氟化碳(a-C:F)薄膜.采用X光电子能谱(XPS)和傅里叶变换红外(FTIR)光谱技术分析了a-C:F薄膜的化学结构.FTIR分析表明,a-C:F薄膜中含有CFx(x=1～3),CF=C以及位于a-C:F交联结构末端的CF2=CF等基团,没有迹象表明有C-H存在.XPS C1s峰各结合态与结合能的对应关系分别为:CF3(295 eV),CF2(293 eV),CF(291 eV),C-O(289 eV),C-CFx(x=1～3)(287 eV)以及位于a-C:F交联结构末端的C-C(285 eV).随着气体质量流量比R的增大,a-C:F薄膜中的F含量和位于a-C:F交联结构末端的C-C含量减小,而交联C-CFx含量增大.而且当气体质量流量比R增大时,a-C:F薄膜介电常数随着电子极化减小以及薄膜密度增大从2.1上升到2.4,漏电流随着π价带态和π*导带态之间带隙的减小而上升,薄膜热稳定性随着破坏薄膜交联结构的CF3和CF2=CF等不稳定成分的减少以及C-CFx交联结构的增多而上升.Fluorinated amorphous carbon （a-C：F） films were prepared using ECR-CVD by varying gas mass flow ratio R（R = m（Cn4） ： m（Cn4 ＋ C4F8）） . Chemical compositions and bond structures were investigated by Fourier transform infrared （FTIR） spectroscopy and X-ray photoelectron spectroscopy （XPS）. FTIR analysis indicated that CFx（x = 1 ～ 3）,CF=C, and CF2 = CF that acted as termination groups of cross-linking a-C： F structures were identified in the deposited a-C： F films. However, no sign revealed the existence of C--H in the deposited films. XPS Cls peaks were assigned to CF3（295 eV）, CF2（293 eV）, CF（291 eV）, C-O（289 eV）, C-CFx （x = 1 ～3）（287 eV） and C-C termination bond（285 eV）, respectively. Fluorine content in the a-C：F film and C-C termination bond decreased with increasing R, while concentrations of the cross-linked C-CFx bonds increased. As gas flow ratio R increased, the dielectric constant increased from 2.1 to 2.4 due to reduced electronic polarization and enlarged film density, the leakage current increased due to reduced energy gap between π and π band states, and the thermal stability improved due to decreasing unstable CF3 and CF2 = CF and increasing cross-linked C-CFx structures.

关 键 词：A-C:F 薄膜性能 化学气相沉积 化学组分 

分 类 号：O484.4[理学—固体物理]