HfO2 and Al2O3 gate dielectrics on GaAs grown by atomic layer deposition -: art. no. 152904

High-performance metal-oxide-semiconductor field effect transistors (MOSFETs) on III-V semiconductors have long proven elusive. High-permittivity (high-kappa) gate dielectrics may enable their fabrication. We have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition. As-deposited films are continuous and predominantly amorphous. A native oxide remains intact underneath HfO2 during growth, while thinning occurs during Al2O3 deposition. Hydrofluoric acid etching prior to growth minimizes the final interlayer thickness. Thermal treatments at similar to 600 degrees C decompose arsenic oxides and remove interfacial oxygen. These observations explain the improved electrical quality and increased gate stack capacitance after thermal treatments. (C) 2005 American Institute of Physics.