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Transfer Doping in Diamond for Channel Doping and Electrical Contacts

MetadataDetails
Publication Date2021-08-05
JournalIEEE Transactions on Electron Devices
AuthorsLucas Huddleston, Shamus McNamara
InstitutionsUniversity of Louisville
Citations1

This article reports on the use of transfer doping (TD) to create holes in a diamond substrate using defects in Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> that are located at an energy below the top of the diamond valence band. The energy bands of a metal-Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> -diamond structure are analyzed for use as a method to make electrical contact to the diamond. The structure is also analyzed for use as part of a field-effect transistor, where the metal acts as the gate. While it is found that the metal can easily dominate the charges in a thin Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> layer, preventing efficient TD of the diamond, we found that the use of a thick Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> layer, a high defect density, or a high work function metal can all serve to permit efficient TD. It is shown that a metal-Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> -diamond structure, utilizing a high defect density in a few nm thick Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> layer, can provide a good electrical contact to the diamond because electrons can tunnel through the Al <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;2&lt;/sub> O <sub xmlns:mml=“http://www.w3.org/1998/Math/MathML” xmlns:xlink=“http://www.w3.org/1999/xlink”&gt;3&lt;/sub> layer and because a high hole concentration is formed under the metal contact in the diamond substrate.