Date of Award

12-2015

Degree Type

Thesis

Degree Name

Master of Science

Major

Materials Science and Engineering

Major Professor

Philip D. Rack

Committee Members

Thomas T. Meek, Jason D. Fowlkes

Abstract

In this study, HfO2 [hafnium oxide] thin films are investigated extensively as part of indium gallium zinc oxide (IGZO) thin film transistor (TFT) devices. They are incorporated into the TFTs, both as a gate insulator and a passivation layer. First, the HfO2 [hafnium oxide] films themselves are investigated through an annealing study and through I-V and C-V measurements. Then, HfO2 [hafnium oxide] is suggested as a replacement for commonly used SiO2 [silicon dioxide] gate insulator, as it has a dielectric constant that is 4 – 6 times higher. This higher dielectric constant allows for comparable TFT performance at a lower operation voltage (5 V vs. 20 V). Finally, HfO2 [hafnium oxide] is applied as a passivation layer in IGZO TFTs, and an annealing study is conducted to determine which processing steps will allow for optimal TFT performance. The HfO2 [hafnium oxide] passivation layer proves to show a good level of uniformity. Therefore, taking all results into consideration, both HfO2 [hafnium oxide] gate insulators and passivation layers can be used in conjunction with IGZO TFTs to produce a full electrowetting array, which should prove to be useful in “lab on a chip” studies.

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