Performance Enhancement of InAsSb QW-MOSFETs with in-situ H2 Plasma Cleaning for Gate Stack Formation

Introduction: Antimonide (Sb) based quantum-well (QW) heterostructures such as InAsSb and InGaSb are of interest for III-V CMOS due to their superior electron and hole transport properties, and ability to be grown on a common metaphoric buffer [1-2]. However, a major challenge towards realizing Sb-based complementary MOSFET technology is the successful integration of a high-κ gate dielectric. Sb-based materials when exposed to the atmosphere readily form complex and defective native oxides which results in Fermi level pining and ineffective surface Fermi level modulation. In this work, we integrate an ultra-thinHfO2 dielectric with the GaSb/In0.2Al0.8Sb/ InAs0.8Sb0.2 QW heterostructure (Fig. 1a). Incorporation of in-situ H2 plasma cleaning of GaSb prior to thermal Atomic Layer Deposition (ALD) of HfO2 results in a HfO2/GaSb interface with significantly improved electrical quality; we demonstrate a 35% improvement in the sub-threshold slope (SS) over devices that employ ex-situ chemical cleaning process.