Interface studies of GaAs metal-oxide-semiconductor structures using atomic-layer-deposited HfO_2/Al_2O_3 nanolaminate gate dielectric

摘要

Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75083, USA A systematic capacitance-voltage study has been performed on GaAs metal-oxide-semiconductor (MOS) structures with atomic-layer-deposited HfO_2/Al_2O_3 nanolaminates as gate dielectrics. A HfO_2/Al_O_3 nanolaminate gate dielectric improves the GaAs MOS characteristics such as dielectric constant, breakdown voltage, and frequency dispersion. A possible origin for the widely observed larger frequency dispersion on n-type GaAs than p-type GaAs is discussed. Further experiments show that the observed hysteresis is mainly from the mobile changes and traps induced by HfO_2 in bulk oxide instead of those at oxide/GaAs interface.