PECVD形成纳米级薄膜界面陷阱的物理模型

Physical Model of Interface Trap for Thin Film in Nanometre Range Formed by PECVD

采用雪崩热电子注入技术研究了纳米级富氮 Si Ox Ny 薄膜界面陷阱的物理模型。证实了 PECVDSi Ox Ny 薄膜中界面陷阱来源于悬挂键的物理模型。观察到该纳米膜内存在着受主型电子陷阱 ,随着注入的增长 ,界面上产生的这种陷阱将起主导作用。发现到 Dit随雪崩热电子注入剂量增加而增大 ,禁带上半部 Dit的增大较下半部显著。指出了雪崩注入过程中在 Si Ox Ny 界面上产生两种性质不同的电子陷阱 ,并给出它们能级位置及密度大小关系。揭示出 PECVD法形成的这种纳米膜与快速热氮化制备的薄膜中、氮氧含量不同、界面陷阱特性变化不一样 ,并从薄膜氮化机制予以物理解析。给出了 PECVD形成纳米级薄膜的优化工艺条件 。

Physical model of interface trap for SiO x N y thin film in nanometre range has been studied by means of avalanche hot electron injection. The physical model of interface trap in the thin film which originates from the suspension bond is confirmed. Electron trap of acceptor type, existing in the nanometre film, has been observed. With the increase of avalanche injection, the created electron trap of acceptor type in interface should play a leading role. The D it increased with the injection is discoveried. The densities of upper half part in forbidden band are increased more than that of lower part. It is indicated that two kinds of electron traps with different properties, are generated in the SiO x N y interface during injection. The relationships between the energy levels and density are provided. It is revealed that nanometre film formed by PECVD and the film fabricated by RTN process have different changes in interface trap characteristics, as the nitrogen and oxygen contents are different. The physical explanation is supplied. The process condition of the PECVD in nanometre film is optimized. The thin film formed by the optimized condition possess better interface trap characteristic and other good physical and electrical characteristics.