Ultimate low leakage and EOT of high- κ dielectric using transferred metal electrode

Weiqi Dang; Zheyi Lu; Bei Zhao; Bo Li; Jia Li; Hongmei Zhang; Rong Song; Mongur Hossain; Zhikai Le; Yuan Liu; Xidong Duan

doi:10.1088/1361-6528/ac76d4

Ultimate low leakage and EOT of high- κ dielectric using transferred metal electrode

Nanotechnology. 2022 Jul 4;33(39). doi: 10.1088/1361-6528/ac76d4.

Authors

Weiqi Dang¹, Zheyi Lu², Bei Zhao¹, Bo Li², Jia Li¹, Hongmei Zhang¹, Rong Song¹, Mongur Hossain¹, Zhikai Le², Yuan Liu², Xidong Duan¹

Affiliations

¹ Hunan Key Laboratory of Two-Dimensional Materials and State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China.
² Hunan Key Laboratory of Two-Dimensional Materials, Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China.

PMID: 35675787
DOI: 10.1088/1361-6528/ac76d4

Abstract

The increase of gate leakage current when the gate dielectric layer is thinned is a key issue for device scalability. For scaling down the integrated circuits, a thin gate dielectric layer with a low leakage current is essential. Currently, changing the dielectric layer material or enhancing the surface contact between the gate dielectric and the channel material is the most common way to reduce gate leakage current in devices. Herein, we report a technique of enhancing the surface contact between the gate dielectric and the metal electrode, that is constructing an Au/Al₂O₃/Si metal-oxide-semiconductor device by replacing the typical evaporated electrode/dielectric layer contact with a transferred electrode/high-κdielectric layer contact. The contact with a mild, non-invasive interface can ensure the intrinsic insulation of the dielectric layer. By applying 2-40 nm Al₂O₃as the dielectric layer, the current density-electrical field (J-E) measurement reveals that the dielectric leakage generated by the transferred electrode is less than that obtained by the typical evaporated electrode with a ratio of 0.3 × 10¹ ∼ 5 × 10⁶atV_bias = 1 V. Furthermore, atJ = 1 mA cm^-2, the withstand voltage can be raised by 10⁰-10²times over that of an evaporated electrode. The capacitance-voltage (C-V) test shows that the transferred metal electrode can efficiently scale the equivalent oxide layer thickness (EOT) to 1.58 nm, which is a relatively smaller value than the overall reported Si-based device's EOT. This finding successfully illustrates that the transferred electrode/dielectric layer's mild contact can balance the scaling of the gate dielectric layer with a minimal leakage current and constantly reduce the EOT. Our enhanced electrode/dielectric contact approach provides a straightforward and effective pathway for further scaling of devices in integrated circuits and significantly decreases the overall integrated circuit's static power consumption (ICs).

Keywords: EOT; Si; leakage current; transferred electrode.