金属—氮氧化硅—硅电容在本征击穿前的漏电特性

Leakage Current Characteristics of Metal-Oxynitride-Silicon Capacitors before Intrinsic Dielectric Breakdown

本文的实验结果表明,从6MV/cm到14MV/cm的外加电场范围内,在氮氧化硅膜的漏电机理与常规方法生长的氧化硅的不同。氮氧化硅膜漏电机理可分为三种。当电场小于8MV/cm时,漏电是由于注入电子的直接隧穿填充绝缘体中的浅陷阱而引起的。在高场范围(>10MV/cm)Fowler-Nordheim(FN)效应占支配地位。这些机理与介质膜的制备条件有关。在中等电场区域,注入电子能通过FN电流和直接隧穿到达能被填充的陷阱,从而使漏电流产生准态饱和。另一方面,随着氮化的继续,可观察到在漏电流一电压特性中的台阶和在电流的电场依赖性的逆转行为。

This study reveals that the mechanism of leakage current in the oxynitride is deviating from that in conventional grown silicon oxide in the electric field ranging trom 6MV/cm to 14MV/cm and suggests that the electronic conduction is governed by three different mechanisms.The current conduction at electric field lower than 8MV/cm is due to the tunneling of electrons into the shallow traps in the insulator.In high-field region (>10MV/cm),Fowler-Nordheim(FN)effect becomes dominant but depends on the dielectrics preparation conditions.In moderate field region,traps can be filled by both FN current and direct tunneling of electron into the traps.It results in a quasi-saturation in the leakage current.On the other hand,as the nitrida-tion proceeds,turnaround behaviors are found in leakage current level,ledge in current-voltage characteristics,and fied-dependency of the current.