A New Multipulse Technique for Probing Electron Trap Energy Distribution in High- $kappa$ Materials for Flash Memory Application

摘要

A new discharge-based multipulse technique has been developed in this paper, which overcomes the shortcomings of the existing techniques, such as the charge pumping, charge injection and sensing, and two-pulse $C$–$V$ techniques. It captures the energy signature for electron traps across high-$ kappa$ materials and can be a useful tool for material selection during technology development. Trap distributions in $hbox{HfO}_{2}$, $hbox{Al}_{2}hbox{O}_{3}$, and HfAlO have been compared to identify the effects of material variation. It is observed that hafnium gives the shallow traps at about 0.45 eV above the silicon conduction band bottom (Si $E_{rm CB})$, and the deep traps at 0.8 eV below the Si $E_{rm CB}$ are caused by aluminum. HfAlO combines the features in $hbox{HfO}_{2}$ and $hbox{Al}_{2}hbox{O}_{3}$. A peak near the Si $E_{rm CB}$ has been observed in all the three materials.