Investigation of Ohmic Contact Resistance, Surface Resistance, and Channel Resistance for Hydrogen-Terminated Diamond MOSFETs.

The ohmic contact resistance (${R}_{C}$), surface resistance (${R}_{S}$), and channel resistance (${R}_{\text {CH}}$) of hydrogen-terminated diamond (H-diamond) MOSFETs were investigated in this study. Planar-type and T-type H-diamond MOSFETs were employed to analyze them. Because no interspaces exist between the source–drain and gate electrodes for the T-type H-diamond MOSFETs, then ${R}_{S}$ is zero. Both planar-type and T-type MOSFETs show low leakage current densities and good operations. By considering the relationships between the total resistance (${R}_{ \mathrm{\scriptscriptstyle ON}}$) and 1/ $\vert $ gate voltage-threshold voltage $\vert $ , ${R}_{C}$ and ${R}_{\text {CH}}$ for the T-type H-diamond MOSFET at a gate voltage of −10.0 V are determined to be 13.8 and 21.8 $\Omega \cdot $ mm, respectively. As ${R}_{C}$ for both MOSFETs is the same, ${R}_{S}$ and ${R}_{\text {CH}}$ for the planar-type H-diamond MOSFET are deduced to be 90.0 and 15.8 $\Omega \cdot $ mm, respectively. ${R}_{S}$ accounts for 75.3% of ${R}_{ \mathrm{\scriptscriptstyle ON}}$ for the planar-type H-diamond MOSFET, which is the main reason for its lower drain current and extrinsic transconductance than those of the T-type MOSFET. Although ${R}_{S}$ is suppressed for the T-type H-diamond MOSFET, ${R}_{C}$ occupies 38.8% of ${R}_{ \mathrm{\scriptscriptstyle ON}}$. To further improve the performance of the H-diamond MOSFETs, it is important to eliminate ${R}_{S}$ and decrease ${R}_{C}$ to further improve the electrical properties of the H-diamond MOSFETs. [ABSTRACT FROM AUTHOR]