Boron-Doped Diamond MOSFETs With High Output Current and Extrinsic Transconductance

Abstract

Boron-doped diamond (B-diamond) metal–oxide–semiconductor (MOS) capacitor and MOS field-effect transistor (MOSFET) are fabricated on a flat diamond epitaxial layer. Their electrical properties and thermal stabilities after annealing at 500 °C are investigated. Annealing makes the leakage current density of the B-diamond MOS capacitor increase slightly. There is a larger stretch-out for the capacitance-voltage curve in the depletion region after annealing than that before annealing. The drain-current maxima for the as-fabricated and 500 °C-annealed MOSFETs are obtained as −0.49 and −0.60 mA/mm, respectively. Extrinsic transconductance maxima are 18.7 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$21.4~\mu \text{S}$ </tex-math></inline-formula> /mm, respectively. These obtained values are considerably larger than those obtained by the previously reported B-diamond MOSFETs.