衬底热空穴注入下的薄栅氧化层击穿特性

利用衬底热空穴(SHH)注入技术,分别定量研究了热电子和空穴注入对薄栅氧化层击穿的影响,讨论了不同应力条件下的阈值电压变化.阈值电压的漂移表明是正电荷陷入氧化层中,而热电子的存在是氧化层击穿的必要条件.把阳极空穴注入模型和电子陷阱产生模型统一起来,提出了薄栅氧化层的击穿是与电子导致的空穴陷阱相关的.研究结果表明薄栅氧化层击穿的限制因素依赖于注入热电子量和空穴量的平衡.认为栅氧化层的击穿是一个两步过程.第一步是注入的热电子打断Si一O键,产生悬挂键充当空穴陷阱中心,第二步是空穴被陷阱俘获,在氧化层中产生导电通路,薄栅氧化层的击穿是在注入的热电子和空穴的共同作用下发生的.

Substrate Hot Holes Injection Induced Breakdown Characteristics of Thin Gate Oxides

A substrate hot holes injection method is used to quantitatively examine the roles of electrons and holes separately in thin gate oxides breakdown. The shift of threshold voltage under different stress is discussed. It is indicated that positive charges are trapped in SiO2 while hot electrons are necessary for SiO2 breakdown. The anode holes injection model and the electron traps generation model is linked into a consistent model ,describing the oxide wearout as an electron-correlated holes trap creati on process. The results show that the limiting factor in thin gate oxides breakdown depends on the balance between the amount of injected hot electrons and holes. The gate oxides breakdown is a two-step process. The first step is hot electron's breaking Si-O bonds and producing some dangling bonds to be holes traps. Then the holes are trapped and a conducted path is produced in the oxides. The joint effect of hot electrons and holes makes the thin gate oxides breakdown complete.