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WO3 Passivation of Access Regions in Diamond MOSFETs

MetadataDetails
Publication Date2022-04-18
JournalIEEE Transactions on Electron Devices
AuthorsAlon Vardi, Moshe Tordjman, R. Kalish, Jesús A. del Alamo
InstitutionsTechnion – Israel Institute of Technology, Massachusetts Institute of Technology

We study the impact of access region passivation on the electrical characteristics of hydrogen-terminated diamond MOSFETs with tungsten Carbide (WC) edge contacts. Our experiments reveal a significant improvement to both contact and extrinsic channel sheet resistance once the access regions are passivated with WO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> , indicating that WO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> is an effective surface transfer-doping agent. We analyze a peculiar bump that appears in the subthreshold characteristics of the devices that prevents their effective turn-off. The bump is found to be mitigated when the access regions are passivated by WO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> . Poisson-Schrödinger (P-S) simulations suggest that this bump arises from the field-effect action by the gate over the access region immediately adjoining the gate. This parasitic field effect arises when the surface is unpinned and with a light hole concentration. Owing to its increased surface transfer doping, the use of WO <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> as surface passivation is effective in delivering a sharp device turn-off.