Lg = 100 nm In0.7Ga0.3As quantum well metal-oxide semiconductor field-effect transistors with atomic layer deposited beryllium oxide as interfacial layer

Abstract

In this study, we have fabricated nanometer-scale channel length quantum-well (QW) metal-oxide-semiconductor field effect transistors (MOSFETs) incorporating beryllium oxide (BeO) as an interfacial layer. BeO has high thermal stability, excellent electrical insulating characteristics, and a large band-gap, which make it an attractive candidate for use as a gate dielectric in making MOSFETs. BeO can also act as a good diffusion barrier to oxygen owing to its small atomic bonding length. In this work, we have fabricated In0.53Ga0.47As MOS capacitors with BeO and Al2O3 and compared their electrical characteristics. As interface passivation layer, BeO/HfO2 bilayer gate stack presented effective oxide thickness less 1 nm. Furthermore, we have demonstrated In0.7Ga0.3As QW MOSFETs with a BeO/HfO2 dielectric, showing a sub-threshold slope of 100 mV/dec, and a transconductance (gm,max) of 1.1 mS/μm, while displaying low values of gate leakage current. These results highlight the potential of atomic layer deposited BeO for use as a gate dielectric or interface passivation layer for III–V MOSFETs at the 7 nm technology node and/or beyond.