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

• Published in: IEEE transactions on electron devices 2022-03, Vol.69 (3), p.1181-1185
• Main Authors: Liu, Jiangwei, Ohsato, Hirotaka, Da, Bo, Koide, Yasuo
• Format: Article
• Language: English
• Subjects: Contact resistance; Diamond; Diamonds; Electric contacts; Electrical properties; Electrodes; Leakage current; Logic gates; MOSFET; MOSFETs; Ohmic contacts; Plasma temperature; resistance; Surface resistance; Threshold voltage; Transconductance
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2022.3140699

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,