The Role of Nonidealities in the Scaling of MoS2 FETs
| Autor: | Alessandra Leonhardt, Daniele Chiappe, César J. Lockhart de la Rosa, Anda Mocuta, Philippe Matagne, Stefan De Gendt, Anh Khoa Augustin Lu, Marc Heyns, Devin Verreck, Goutham Arutchelvan, Geoffrey Pourtois, Iuliana Radu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Physics Condensed matter physics Schottky barrier Semiclassical physics Charge density Schottky diode Equivalent oxide thickness Charge (physics) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials 0103 physical sciences Density functional theory Electrical and Electronic Engineering 0210 nano-technology Scaling |
| Zdroj: | IEEE Transactions on Electron Devices. 65:4635-4640 |
| ISSN: | 1557-9646 0018-9383 |
| DOI: | 10.1109/ted.2018.2863750 |
| Popis: | 2-D material FETs hold the promise of excellent gate control, but the impact of nonidealities on their performance remains poorly understood. This is because of the need, so far, to use computationally intensive nonequilibrium Green’s function (NEGF) simulations. Here, we therefore use a semiclassical model to investigate the role of nonidealities in the scaling of back-gated (BG) and top-gated (TG) monolayer MoS2 FETs. We verify the electrostatics and transport of the semiclassical model with density functional theory-based NEGF simulations and calibrate nonidealities, such as interface traps ( ${D}_{\textsf {it}}$ ) and Schottky contact barrier height ( $\phi _{\textsf {SB}}$ ) to experimental monolayer and bilayer MoS2 FETs. We find that among the nonidealities, ${D}_{\textsf {it}}$ has the strongest subthreshold swing impact with 70 mV/dec obtainable in BG devices for a ${D}_{\textsf {it}}$ of $5\times {10}^{11}$ cm−2eV $^{-1}$ , an equivalent oxide thickness (EOT) of 1 nm, and a channel length ( ${L}_{\textsf {ch}}$ ) of 5 nm. For scaled EOT, $\phi _{\textsf {SB}}$ only strongly impacts ${I}_{ \mathrm{\scriptscriptstyle ON}}$ for the TG case, as the overlapping gate thins the Schottky barriers in the BG case. We show in TG devices that a spacer of only 5 nm results in a 1000-fold drop in ${I}_{ \mathrm{\scriptscriptstyle ON}}$ because of the nonidealities. We propose positive spacer oxide charge as a solution and show that a charge density of above 1013 cm−2 is required to fully recover the device performance. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|