Over 1 A/mm drain current density and 3.6 W/mm output power density in 2DHG diamond MOSFETs with highly doped regrown source/drain

This paper reports the direct current and radio frequency characteristics of two-dimensional hole gas (2DHG) diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with microwave- plasma-chemical-vapor-deposition regrown P++-diamond (B approximate to 1 x 10(22) cm(-3)) layers as their source and drain regions. To evaluate the ohmic contact resistance, two patterns of transmission line method were fabricated-one with P++-diamond/2DHG diamond interfaces and the other with only the P++-diamond layer. Three resistance components (metal/P++-diamond contact resistance (0.39 Omega mm), P++-diamond access resistance, and P++-diamond/2DHG contact resistance (-0.65 Omega mm) were evaluated for the first time. The introduction of the P++ -diamond ohmic contacts generated a drain current density of 1 A/mm and an output power density of 3.6 W/mm at a quiescent drain voltage ( V-DS(, Q)) of -50 Vat 1 GHz; an output power of 1.7 W was achieved at a Vps, Q of -40 V at 1 GHz with a 1 mm gate width. These values were obtained in 2DHG diamond MOSFETs with a regrown P++-diamond layer with 1 mu m gate length. These results indicate that regrown P++-diamond has the potential to improve the drain current density and output power density of 2DHG diamond field-effect transistors. (C) 2021 Published by Elsevier Ltd.

Automated summary

This study investigates the DC and RF characteristics of 2DHG diamond MOSFETs with regrown P++-diamond layers as source and drain. The results demonstrate that regrown P++-diamond has the potential to improve drain current density and output power density of 2DHG diamond field-effect transistors.