Date of Award

3-1-2022

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

First Advisor

James M. Sattler, PhD

Abstract

Gallium oxide is a relatively new semiconductor material with characteristics auspicious for high frequency and high-voltage applications. Although several research groups have already demonstrated radio-frequency (RF) devices on Ga2O3 with remarkable features, there is still room for improvement. For instance, the operating frequency of RF field-effect transistors (FET) decreases with the parasitic capacitance, which can be counteracted by higher gate capacitance. Implementing ferroelectric dielectrics with suitable parameters in Ga2O3 FET promises to enhance the gate capacitance and therefore increase operating frequency. This work investigated the effect of various factors (film composition, film thickness, TiN thickness, and annealing temperature) on the polarization of hafnium-based ferroelectrics to better understand how to finetune the ferroelectric parameters, thus leading to the successful integration of these materials with Ga2O3 substrates. A factorial experiment was set up, which included the fabrication and characterization of metal-ferroelectric-metal (MFM) capacitors. Polarization-electric field data was collected on all samples and evaluated statistically using analysis of variance (ANOVA). Results showed that HZO composition and annealing temperature were key factors in inducing ferroelectricity in these films while also highlighting intricate interactions between all the factors studied.

AFIT Designator

AFIT-ENG-MS-22-M-058

Comments

A 12-month embargo was observed.

Cleared for public release: 88ABW-2022-0588

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