C-Si bonded two-dimensional hole gas diamond MOSFET with normally-off operation and wide temperature range stability

A C-Si bonded SiO2/diamond interface is formed under a SiO2 mask during the selective diamond growth at a high temperature in a H-2 atmosphere including methane (5%). A few monolayers with C-Si bonding at the SiO2/diamond surface are confirmed through X-ray photoelectron spectroscopy at the Cls and Si2p core levels from 290 eV to 271 eV and 107 eV-95 eV, respectively. In addition, secondary ion mass spectroscopy results suggest that the C-Si bonds, and not C-H bonds, are majority at the interface and are mainly responsible for the field effect transistor (FET) operation. Two-dimensional hole gas C-Si diamond metal-oxide-semiconductor FET (MOSFETs) are fabricated using the C-Si diamond subsurface as a p-channel. The MOSFETs in which the actual length from the source to the drain (L-SD) is 12 mu m-6 mu m show appreciable field-effect mobility (e.g. 140 cm(2)V(-1)s(-1) at L-SD = 12 mu m and 300 K) and normally-off operation. The wide temperature characteristics of the C-Si MOSFETs are confirmed and the device shows high stability, and a high on/off ratio of 106 is maintained at 673 K. The C-Si bonding at the Si02 /diamond interface provide a lower interface state density which makes the MOSFET show high drain current density and field-effect mobility with normally-off operation. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A C-Si bonded SiO2/diamond interface was formed during selective diamond growth at high temperature in a H-2 atmosphere with 5% methane. The resulting C-Si diamond MOSFETs exhibited high stability, field-effect mobility, and a high on/off ratio, showcasing potential for advanced electronic applications.