Normally-off Hydrogen-Terminated Diamond Field-Effect Transistor with SnOx Dielectric Layer Formed by Thermal Oxidation of Sn

Shi He; Yanfeng Wang; Genqiang Chen; Juan Wang; Qi Li; Qianwen Zhang; Ruozheng Wang; Minghui Zhang; Wei Wang; Hongxing Wang

doi:10.3390/ma15145082

Normally-off Hydrogen-Terminated Diamond Field-Effect Transistor with SnO_x Dielectric Layer Formed by Thermal Oxidation of Sn

Materials (Basel). 2022 Jul 21;15(14):5082. doi: 10.3390/ma15145082.

Authors

Shi He^{1

2}, Yanfeng Wang^{1

2}, Genqiang Chen^{1

2}, Juan Wang^{1

2}, Qi Li^{1

2}, Qianwen Zhang^{1

2}, Ruozheng Wang^{1

2}, Minghui Zhang^{1

2}, Wei Wang^{1

2}, Hongxing Wang^{1

2}

Affiliations

¹ Key Laboratory of Physical Electronics and Devices, Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
² Institute of Wide Band Gap Semiconductors, School of Electronics and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China.

Abstract

SnO_x films were deposited on a hydrogen-terminated diamond by thermal oxidation of Sn. The X-ray photoelectron spectroscopy result implies partial oxidation of Sn film on the diamond surface. The leakage current and capacitance-voltage properties of Al/SnO_x/H-diamond metal-oxide-semiconductor diodes were investigated. The maximum leakage current density value at -8.0 V is 1.6 × 10^-4 A/cm², and the maximum capacitance value is measured to be 0.207 μF/cm². According to the C-V results, trapped charge density and fixed charge density are determined to be 2.39 × 10¹² and 4.5 × 10¹¹ cm^-2, respectively. Finally, an enhancement-mode H-diamond field effect transistor was obtained with a V_TH of -0.5 V. Its I_DMAX is -21.9 mA/mm when V_GS is -5, V_DS is -10 V. The effective mobility and transconductance are 92.5 cm²V^-1 s^-1 and 5.6 mS/mm, respectively. We suspect that the normally-off characteristic is caused by unoxidized Sn, whose outermost electron could deplete the hole in the channel.

Keywords: FET; SnOX; diamond; normally-off; thermal oxidation.

Abstract

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