Temperature dependence of diamond MOSFET transport properties

The electrical properties of p-channel diamond metal-oxide-semiconductor FETs (MOSFETs) have been investigated for temperatures ranging from 6.5 K to 673 K. Diamond MOSFETs exhibit typical normally-off MOSFET features from 6.5 K to 623 K. Despite the high impurity ionization energy in diamond (donor: 0.58 eV, acceptor: 0.38 eV), an inversion channel is formed in diamond MOSFETs at low temperature (up to 6.5 K). oreover the high-temperature measurements induce an irreversible shift in the threshold voltage of diamond MOSFETs (from -6.5 V to -3.15 V), leading to a significant improvement of the room temperature drain current. The threshold voltage shift results from a reduction of the total density of the extrinsic charges at Al2O3/diamond interface because of unintentional post-deposition annealing of the Al2O3 gate oxide at high temperature. (C) 2020 The Japan Society of Applied Physics