Graduation Semester and Year

2022

Language

English

Document Type

Thesis

Degree Name

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

First Advisor

Jin Seong Koh

Abstract

The Fermi-Dirac thermal excitation of electrons results in unwanted off-state leakage currents in metal-oxide-semiconductor field-effect transistors (MOSFETs), leading to excessive power consumption in modern electronic devices. The electron thermal excitation results in a theoretical subthreshold slope limit of 60 mV/decade at room temperature, which forces the devices to use a high supply voltage leading to high power consumption. This study investigates a new architecture capable of suppressing electron thermal excitation by using a quantum well (QW) as an energy filter. The QW energy filter is composed of a tunneling barrier 1 (0.5 to 1 nm Al2O3 or 0.3-1 nm Si3N4 or no tunneling barrier) a quantum well (QW) layer (3-5 nm tin oxide, SnO2), and a tunneling barrier 2 (native silicon dioxide, SiO2). The energy filter layers are sandwiched between a chromium electrode and silicon. This energy-filtering structure makes it possible to inject cold electrons into silicon with abrupt current jumps, which correspond to the alignment of the QW levels with the conduction band edge of silicon. Differential conductance (dI/dV) plots show extremely narrow peaks, with their FWHMs (full widths at half maximum) only 0.025mV, corresponding to an effective electron temperature of 0.08 Kelvin at room temperature. This cold electron injection to Si at room temperature has a potential to create transistors that operate with extremely little energy consumption.

Keywords

Cold electron transport

Disciplines

Engineering | Materials Science and Engineering

Comments

Degree granted by The University of Texas at Arlington

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