InGaAs MOS Transistors Fabricated through a Digital-Etch Gate-Recess Process and the Influence of Forming Gas Anneal on Their Electrical Behavior

Abstract

InGaAs channel Implant-Free Quantum-Well (IFQW) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET) were fabricated and characterized using a digital etch gate-recess process. InGaAs surface morphology after the digital etching using different chemistries was investigated by Atomic Force Microscopy (AFM). The digital etch rate was characterized both electrically and physically. The resulting InGaAs surface properties were evaluated by characterizing the IFQW-MOSFETs with an atomic-layer-deposited (ALD) Al2O3 gate dielectric. Well-behaved MOSFET devices were demonstrated indicating the excellent surface properties after the digital etch. Impact of thermal anneals on the device performance was systematically studied and significant improvements were observed after forming gas anneal (FGA). The resulting interface state density (Dit) profiles were characterized applying the conductance method.