ADVANCED GERMANIUM-TIN P-CHANNEL METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS

Abstract

Germanium-tin (GeSn) alloy is a promising Group IV semiconductor due to its potential applications in both nanoelectronic and photonic devices. Incorporation of Sn into Ge reduces the effective mass of GeSn, enhances the carrier mobility, and could be used as the channel material in metal-oxide-semiconductor field-effect transistors (MOSFETs) for high performance logic applications. This thesis developed the high mobility GeSn p-channel MOSFETs. Firstly, GeSn p-MOSFETs with increased Sn composition is fabricated. The effect of sulfur passivation on the gate stack quality is thoroughly studied. Secondly, a novel GeSn-on-insulator (GeSnOI) substrate is formed using direct wafer bonding technique. This provides a new platform for monolithic integration of electronic and photonic devices using Group IV-only materials. Thirdly, GeSn p-FinFETs with excellent electrical characteristics are realized, which could be attributed to the high quality CVD-grown GeSn material, the GeSnOI layer structure, and excellent gate control using FinFET device architecture.