PECVD形成纳米级薄膜界面陷阱特性的雪崩热电子注入研究

Study on avalanche hot-electron injection of interface trap characteristic 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SiOxNy薄膜界面陷阱特性。证实了PECVD SiOxNy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。发现到界面陷阱密度随雪崩热电子注入剂量增加而增大,禁带上半部增大得较下半部显著。指出了雪崩注入过程中在SiOxNy界面上产生两种性质不同的电子陷阱,并给出它们在禁带中的位置与密度大小关系。揭示出PECVD法形成的SiOxNy纳米膜与快速热氮化制备的这种薄膜中、氮氧含量不同、界面陷阱特性变化关系不一样,并从形成薄膜氮化机制上予以合理的物理解析。给出了PECVD形成纳米级薄膜的优化工艺条件。

Interface trap Characteristic for SiOxNy thin film in nanometre range has been studiedby means of avalance hot-electron injection technique. The physical model of interface trap in PECVDSiOxNythin film which is originated by the suspension bond was confirmed. With the increase ofavalanche injection, the created electron trap of acceptor type in interface shall play a leading role.The interface trap density increased with the avalanche injection dose is discoveried. The densitiesof upper half-part in forbidden band are increased more markedly than that densities of below half-part. It is indicated that two kinds of electron traps, which have different properties, were generatedin the Si/PECVD SiOxNy interface during avalanche injection. The positions in forbidden band andquantitative densities relationship of these two electron traps are provided. It is revealed thatnanometre SiOxNy film formed by PECVD and the film fabricated by RTN possess have different changerelationships of interface trap characteristic, as the nitrogen and oxygen contents are different. Thereasonable physical explanation of nitrided mechanism for formed film is supplied. The processcondition of the film in nanometre range formed by PECVD is optimized.