−400 mA mm−1Drain Current Density Normally-Off Polycrystalline Diamond MOSFETs
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-03-16 |
| Journal | IEEE Electron Device Letters |
| Authors | Xiaohua Zhu, Siwu Shao, Yu Hao Chang, Runming Zhang, Sylvia Yuk Yee Chung |
| Institutions | Waseda University, University of Science and Technology Beijing |
| Citations | 7 |
Abstract
Section titled “Abstract”This letter reports a high drain current density and normally-off operation metal-oxide-semiconductor field-effect transistors (MOSFETs) with a gate insulator of 100 nm-Al<sub>2</sub>O<sub>3</sub>. A heavily boron-doped layer as the source/drain region was deposited on a (110) polycrystalline diamond substrate to achieve a low ohmic contact resistance. The MOSFETs demonstrate a maximum current density of −400 mA mm<inline-formula> <tex-math notation=“LaTeX”>$^{-{1}}$ </tex-math></inline-formula> normalized by gate width and a maximum current density of <inline-formula> <tex-math notation=“LaTeX”>$- 2000,,\mu \text{m}$ </tex-math></inline-formula> mA mm<sup>−1</sup> normalized by gate length and gate width, which are the highest values for normally-off diamond FETs. The Grain boundaries (GBs) and the nitrogen impurities (<inline-formula> <tex-math notation=“LaTeX”>$\sim {3},,\times ,,{10}^{{17}}$ </tex-math></inline-formula> cm<inline-formula> <tex-math notation=“LaTeX”>$^{-{3}}$ </tex-math></inline-formula>) as ionized donors in the channel region caused the threshold voltage (<inline-formula> <tex-math notation=“LaTeX”>${V}_{\text {th}}$ </tex-math></inline-formula>) to shift in the negative direction, exhibiting normally-off characteristics. This technique provides a promising method to achieve high-performance diamond devices, and help improve safety and save energy in switching systems.