氧化物薄膜晶体管刻蚀阻挡层PECVD沉积条件研究

为实现氧化物TFT(Indium Gallium Zinc Oxide Thin Film Transistor,IGZO TFT)特性的最优化,采用I-V数据和SEM(Scanning Electron Microscope)图片研究蚀阻挡层(Etch-Stop Layer,ESL)沉积条件与氧化物TFT特性的关系。通过调整沉积温度、正负极板间距、压力和功率,分析了PECVD沉积ESL SiO2的成膜规律,并对所得到的TFT进行了特性分析。发现ESL膜层致密性过差时,后期高温工艺会造成水汽进入IGZO半导体膜层,从而引起TFT特性恶化。而采用高温、高压力等方法取得高致密性的ESL膜层由于高强度等离子体对IGZO本体的还原反应也会致使TFT特性劣化。结果表明,在保证膜层致密性前提下,等离子体对IGZO本体伤害最小的ESL沉积条件才是最优化的ESL沉积条件。

Etch-stop layer plasma chemical enhanced vapor deposition for oxide thin-film-transistor

In order to optimize the oxide semiconductor TFT character,I-V and SEM data is used to study the dependence of oxide semiconductor TFT character on ESL deposition. The rule of ESL silicon oxide deposition was studied by tuning the temperature,spacing,pressure and power of the deposition. Moreover, the TFT characteristic was also used to analysis ESL silicon oxide deposition. It is found that the TFT will be degraded when the ESL film is loose with multihole structure. The degradation must be attributed to the damage of IGZO semiconductor by the invasion of the vapor caused by later high temperature process. However,the TFT is also bad when the ESL film is dense manufacturing by high temperature or high pressure of deposition because of the reduction reaction between IGZO semiconductor and the enhanced plasma. The most optimization process will be obtained by dense ESL film while the disposition should be minimum damage to IGZO semiconductor.