Drain Current Density Over 1.1 A/mm in 2D Hole Gas Diamond MOSFETs With Regrown p++-Diamond Ohmic Contacts

摘要

We report two-dimensional hole gas (2DHG) diamond field-effect transistors (FETs) with microwave plasma chemical vapor deposition (MPCVD)-regrown p(++)-diamond (B concentration similar to 1x10(22) /cm(3)) ohmic contacts. The heavily doped p(++)-diamond shows low ohmic contact resistance of 1.1 Omega center dot mm, which is the lowest value reported in diamond to date. In addition, the p(++)-diamond with a TiC also offers much stronger metal adhesion when compared with previous Au/hydrogen- terminated diamond surfaces and is suitable for industrial use. Benefiting from the low contact resistance of the p(++)-diamond layer, a maximum drain current density of 1170 mA/mm and an ON-resistance of 8.9 Omega center dot mm were demonstrated in a 2DHG diamond metal-oxide-semiconductor FET with a 1 mu m gate length. These results indicate that the regrown p(++)-diamond ohmic contacts will make it possible to realize further improvements in themaximumdrain current density of 2DHG diamond FETs.