Boron-Doped Diamond MOSFETs With Gradual Channel Doping Density

The growth of gradual boron-doped diamond epitaxial layer was achieved by microwave plasma chemical vapor deposition (MPCVD). Secondary ion mass spectrometry (SIMS) results show that the effective doping concentration range is from 10(15) cm(-3) to 10(19) cm(-3), and the doping layer thickness is about 45 nm. Boron-doped diamond Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) was prepared by using 300 degrees C atomic layer deposition (ALD) Al2O3 as gate dielectric. The maximum output current and transconductance of the device reach -1.2 mA/mm and 127 mu S/mm, respectively, both of which are higher than the reported. Meanwhile, the device has a low threshold voltage of 3.3 V. We suggested that the low ohmic contact resistance (RC) induced by the high doping density on the sample surface and the thin doping layer thickness contribute to these high device performances.