Diamond Field-Effect Transistors With V<sub>2</sub>O<sub>5</sub>-Induced Transfer Doping: Scaling to 50-nm Gate Length
Kevin G. Crawford, James Weil, Pankaj B. Shah, Dmitry Ruzmetov, Mahesh R. Neupane, Khamsouk Kingkeo, A. Glen Birdwell, Tony Ivanov
Abstract
We report on the fabrication and measurement of hydrogen-terminated diamond field-effect transistors (FETs) incorporating V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> as a surface acceptor material to induce transfer doping. Comparing a range of gate lengths down to 50 nm, we observe inversely scaling peak output current and transconductance. Devices exhibited a peak drain current of ~700 mA/mm and a peak transconductance of ~150 mS/mm, some of the highest reported thus far for a diamond metal semiconductor FET (MESFET). Reduced sheet resistance of the diamond surface after V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> deposition was verified by four probe measurement. These results show great potential for improvement of diamond FET devices through scaling of critical dimensions and adoption of robust transition metal oxides such as V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> .