Passivation and integration of atomically-thin transition metal dichalcogenide electronics
Abstract/Contents
- Abstract
- The continued scaling and diversification of transistors, the bedrock of integrated electronics, requires novel material and design paradigms beyond the 10 nm technology node. Two-dimensional Transition Metal Dichalcogenide (TMD) nanosheets offer the potential for pristine, atomically-thin devices. Nonetheless, their development is hindered by issues of contact resistance, poor gate dielectric integration, and ambient degradation. In addition, few studies have focused on moderate-gap TMDs, comparable to or lower than bulk silicon at ~1.1 eV. This work introduces a methodology of air-free fabrication and VLSI-compatible dielectric passivation of TMDs, preserving intrinsic properties at the ultimate thickness limit. This is first applied to the Group-6 tellurides, WTe2 and MoTe2. The former, an anisotropic semimetal, is found to support current densities (~50 MA/cm2) higher than traditional metal interconnects, despite a low in-plane thermal conductivity. The latter, a moderate-gap ambipolar semiconductor, is subject to contact engineering for unipolar n-type transport with saturation current densities exceeding 400 µA/µm. High performance n-type transistors are demonstrated, both by exploiting Ag contacts which form interfacial compounds, and by suppressing extreme reactivity with low-work function metals via a one-atom-thick hexagonal boron nitride (h-BN) diffusion barrier. The final sections explore the novel 2D semiconductors HfSe2 and ZrSe2, first stabilized here in the few-layer limit despite extreme ambient sensitivity. Their decomposition is associated with oxidation into amorphous HfOx and ZrOx, high-K dielectrics of immediate technological relevance. Joint theoretical and spectroscopic studies establish indirect band gaps of ~0.9-1.2 eV persisting across monolayers to bulk films. Measured transistors achieve On/Off ratios exceeding 106, alongside respectable current densities and acute sensitivity to interfacial dielectrics, reproducing for the first time several key attributes of silicon in a 2D nanomaterial.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Mleczko, Michal Jakub |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Nishi, Yoshio, 1940- |
| Thesis advisor | Nishi, Yoshio, 1940- |
| Thesis advisor | Pop, Eric |
| Thesis advisor | Wong, Hon-Sum Philip, 1959- |
| Advisor | Pop, Eric |
| Advisor | Wong, Hon-Sum Philip, 1959- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Michal Jakub Mleczko. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | https://purl.stanford.edu/gt695kr8897 |
Access conditions
- Copyright
- © 2016 by Michal Jakub Mleczko
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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