MOSFETs on InP Substrate with LaAlO3/HfO2 Bilayer of Different LaAlO3 Thickness and Single LaXAl1-XO Layer with Different La Doping Level

Abstract

Electrical performances of HfO2-based InP metal-oxide-semiconductor field-effect-transistor (MOSFETs) with different thicknesses of LaAlO3 interfacial layer are compared. With 20Å LaAlO3/28Å HfO2, effective channel mobility increases by 40% and maximum drive current increases by 50% compared with MOSFETS with single 50Å HfO2. Also MOSFETs with single LaXAl1-XO of different La doping level (X =0.25, 0.33, 0.5, 0.67, 0.75) was fabricated. Maximum effective channel mobility of 704 cm2/Vs and maximum drive current of 27mA/mm are achieved in devices with LaXAl1-XO of 33% La doping level (W/L=600μm/20μm, EOT~2.7nm). These results suggest a tradeoff between the interface quality and bulk fixed charge for MOSFETs with LaXAl1-XO.