The effects of controlling InGaAs substrate temperature during electron beam deposition of HfO2 on electrical characteristics of W/HfO 2/n-In0.53Ga0.47As capacitors are investigated. It is found that by depositing a thin HfO2 layer at the interface when substrate temperature is raised to 300 °C, frequency dispersion at depletion and accumulation conditions is reduced and interface state density is lowered regardless of the HfO2 thickness. Cross-sectional transmission electron microscopy images have revealed that the formation of mesoscopic voids in the InGaAs substrate near the interface is suppressed with HfO2deposition at 300 °C at the interface. A band diagram with an additional bulk trap energy level has been proposed to explain the frequency dispersion and conductance peaks at accumulation condition.
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