p型硅MOS结构Si/SiO_2界面及其附近的深能级与界面态

DEEP LEVEL IN BOTH Si/SiO_2 INTERFACE AND ITS NEIGH-BOURHOOD AND Si/SiO_2 INTERFACE STATES IN p TYPE SILICON MOS STRUCTURE

用深能级瞬态谱(DLTS)技术系统研究了Si/SiO_2界面附近的深能级和界面态。结果表明,在热氧化形成的Si/SiO_2界面及其附近经常存在一个浓度很高的深能级,它具有若干有趣的特殊性质,例如它的DLTS峰高度强烈地依赖于温度,以及当栅偏压使费密能级与界面处硅价带顶的距离明显小于深能级与价带顶的距离时,仍然可以观测到一个很强的DLTS峰。另外,用最新方法测量的Si/SiO_2界面连续态的空穴俘获截面与温度有关,而与能量位置无明显关系,DLTS测量的界面态能量分布与准静态C-V测量的结果完全不一致。本文提出的Si/SiO_2界面物理模型能合理地解释上述问题。

The deep level in both Si/SiO2 interface and its neighbourhood and Si/SiO2 interface states have been studied systematically with Deep Level Transient Spectroscopy (DLTS). Experimental results show that a dominant deep level, H (0.494), exits in both Si/SiO2 interface and its neighborhood in MOS structure formed by thermal oxidation. The deep level possesses some interesting properties, for example, its DLTS peak height depends strongly on temperature, and when the gate voltage reduces the interval between. Fermi-level and Si valence band to a value less than that between the deep level and Si valence band, its sharp DLTS peak is still observable. The hole capture cross section of the interface states at Si/SiO2 interface has been found to depend on temperature, measured with a new method[15]. The energy distribution of the interface states measured with DLTS contradicts to the distribution obtained by quasistatic C-V technique. A new physical model of Si/SiO2 interface was proposed, with this model the above stated experimental results can be successfully expounded.