コンダクタンス法を用いたHfO_2/In_<0.53>Ga_<0.47>Asの界面解析(ゲート絶縁薄膜,容量膜,機能膜及びメモリ技術)

概要

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The changes in electrical characteristics of W/HfO_2 or La_2O_3/ In_<0.53>Ga_<0.47>As capacitors by wet chemical treatment before or controlling the substrate temperature during oxide deposition were investigated. HMDS was used as a surface passivator and compared to widely-used sulfur based passivation. Using HMDS resulted in reduced frequency dispersion and interface state densities of W/ La_2O_3/In_<0.53>Ga_<0.47>As capacitors without sacrificing capacitance value in accumulation condition. The effects of controlling InGaAs substrate temperature during electron beam deposition of HfO_2 on electrical characteristics of W/HfO_2/n-In_<0.53>Ga_<0.47>As capacitors are investigated. It is found that by depositing a thin HfO_2 layer at the interface when substrate temperature is raised to 300 ℃, frequency dispersion at depletion and accumulation conditions is reduced and interface state density is lowered regardless of the total HfO_2 thickness. The frequency dispersion in accumulation was investigated through conductance method in various temperatures. A model based on traps residing within the bulk of the semiconductor was proposed which could explain the dispersive nature of capacitance in accumulation.
社団法人電子情報通信学会の論文
2011-06-27