Non-Silicon CMOS Devices and Circuits on High Mobility Channel Materials: Germanium and III-V

Heng Wu, Purdue University

Abstract

With the continuous device scaling down as predicted and required by Moore's law, the silicon complementary metal-oxide-semiconductor (CMOS) technology has been pushed down to 14 nm, approaching its physical limitations. For further developments, novel channel materials, alternative switching mechanisms and new device structures are expected. High mobility materials such as Germanium and III-V compounds have been widely discussed and investigated for post-Silicon technology. However, various problems still exist as showstoppers. In this dissertation, multiple challenges in employing these materials are studied and addressed such as: high-κ dielectrics to semiconductor interface with high quality, low resistivity metal contacts to semiconductor, advanced 3D gate structures and CMOS device integration. This Ph.D. research studies both nMOSFETs and pMOSFETs on non-Silicon substrates with experiments as the focus, including Germanium as the IV group material and lattice-matched InAs/GaSb as the III-V group material. Satisfactory results have been achieved. For the Germanium, 1) surface passivation, 2) contact optimization, 3) high performance Ge nMOSFETs, 4) well-behaved Ge pMOSFETs, 5) ultra device scaling down to deep sub-100 nm, 6) first demonstration of Ge CMOS circuits and 7) rst demonstration of Ge 3D FinFET and nanowire CMOS circuits are included. For the InAs/GaSb, 1) 3D gate structures integration development, 2) first top-down InAs GAA nMOSFETs and 3) GaSb interface passivation techniques are explored. This study demonstrates the promising future of using Germanium and III-V compounds as alternative channel materials to replace Silicon.

Degree

Ph.D.

Advisors

YE, Purdue University.

Subject Area

Engineering|Electrical engineering|Materials science

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