Date of Award

1-1-2015

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Nanoscale Science and Engineering

Program

Nanoscale Engineering

Content Description

1 online resource (vi, 109 pages) : color illustrations

Dissertation/Thesis Chair

Serge Oktyabrsky

Committee Members

Hassaram Bakhru, Alain Diebold, Ernest Levine, Dmitry Veksler

Keywords

electron mobility, III-V Semiconductors, interface trap density, MOSFETs, Metal oxide semiconductor field-effect transistors, Metal oxide semiconductors, Gallium arsenide semiconductors, Indium phosphide, Compound semiconductors, Hall effect devices

Subject Categories

Electrical and Electronics | Nanoscience and Nanotechnology | Physics

Abstract

III-V semiconductors are potential candidates to replace Si as a channel material in next generation CMOS integrated circuits owing to their superior carrier mobilities. Low density of states (DOS) and typically high interface and border trap densities (Dit) in high mobility group III-V semiconductors provide difficulties in quantification of Dit near the conduction band edge. The trap response above the threshold voltage of a MOSFET can be very fast, and conventional Dit extraction methods, based on capacitance/conductance response (CV methods) of MOS capacitors at frequencies <1MHz, cannot distinguish conducting and trapped carriers. In addition, the CV methods have to deal with high dispersion in the accumulation region that makes it a difficult task to measure the true oxide capacitance, Cox value. Another implication of these properties of III-V interfaces is an ambiguity of determination of electron density in the MOSFET channel. Traditional evaluation of carrier density by integration of the C-V curve, gives incorrect values for Dit and mobility. Here we employ gated Hall method to quantify the Dit spectrum at the high-κ oxide/III-V semiconductor interface for buried and surface channel devices using Hall measurement and capacitance-voltage data. Determination of electron density directly from Hall measurements allows for obtaining true mobility values

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