MOSFETs on InP substrate with LaAlO_3/HfO_2 bilayer of different LaAlO_3 thickness and single La_XAl_(1-X)O layer with different La doping level

摘要

Electrical performances of HfO_2-based InP metal-oxide-semiconductor field-effect-transistor (MOSFETs) with different thicknesses of LaAlO_3 interfacial layer are compared. With 20A LaAlO_3/28A HfO_2, effective channel mobility increases by 40% and maximum drive current increases by 50% compared with MOSFETS with single 50A HfO_2. Also MOSFETs with single La_XAl_(1-X)O of different La doping level (X =0.25, 0.33, 0.5, 0.67, 0.75) was fabricated. Maximum effective channel mobility of 704 cm~2/Vs and maximum drive current of 27mA/mm are achieved in devices with La_XAl_(1-X)O 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 La_XAl_(1-X)O.