零偏源MOS结构的栅电荷弛豫机制及近少子带边界面态分布的瞬态谱测定

讨论了小方栅脉冲下零偏置源MOS结构栅电荷弛豫的机制.证明了当费米能级接近少子带边时,引起栅电荷弛豫的起因将由界面态俘获发射电荷的过程变成受其延迟的表面少子扩散漂移过程.对后一过程进行理论分析导出的栅电荷公式与实验取得了一致.在此基础上提出了根据栅电荷波形参数确定栅电荷变化量中界面态贡献的大小,进而测定近少子带边一侧界面态密度的测量原理.获得了覆盖的能量范围一直延伸到距少子带边 0.05 eV处的界面态密度能量分布.在不同类型样品中获得了具有共同特征的结果.

Gate Charge Relaxation Mechanism of MOS Structure with Zero Biased Source and Transient Spectroscopic Measurement of Si/SiO_2 Interface State Distribution near Minority Carrier Band Edge

The gate charge relaxation mechanism of MOS structure with zero biased source regionis investigated under a small gate square pulse.It is demonstrated that when the Fermi levelgoes to the surface minority carrier energy band edge, this mechanism will turn from the car-rier capturing and emitting of interface states to the minority carrier diffusing and driftingdelayed by interface state trapping. The theoretically predicted behaviors of such a minorityarrier transportation are verified by a series of experiments.Based on this theory a new me-surement principle for Si/SiO_2 interface state density near minority carrier band edge is pro-osed and the D_(it)(E) formula is deduced, too. The obtained D(it)(E) distributions show someimportant and common features. Even in the energy position 0.05 eV apart from the minoritycarrier edge reasonable D(it)(E) measurement is also obtainable by this method.