Comparison of the Physical and Electrical Properties of HfO₂/Al₂O₃/HfO₂/GeOx/Ge and HfO₂/Al₂O₃/GeOx/Ge Gate Stacks

Yi-He Tsai; Chen-Han Chou; Hui-Hsuan Li; Wen-Kuan Yeh; Yu-Hsien Lin; Fu-Hsiang Ko; Chao-Hsin Chien

doi:10.1166/jnn.2019.16494

Comparison of the Physical and Electrical Properties of HfO₂/Al₂O₃/HfO₂/GeO_x/Ge and HfO₂/Al₂O₃/GeO_x/Ge Gate Stacks

J Nanosci Nanotechnol. 2019 Aug 1;19(8):4529-4534. doi: 10.1166/jnn.2019.16494.

Authors

Yi-He Tsai¹, Chen-Han Chou², Hui-Hsuan Li³, Wen-Kuan Yeh⁴, Yu-Hsien Lin³, Fu-Hsiang Ko¹, Chao-Hsin Chien²

Affiliations

¹ Graduate Program for Nanotechnology Department of Materials Science and Engineering, National Chiao-Tung University, Hsinchu 30010, Taiwan.
² Department of Electronics Engineering and the Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan.
³ Department of Electronics Engineering, National United University, No. 2, Lienda, Nan Shih Li, Miaoli City, Taiwan 36003, R.O.C.
⁴ National Nano Device Laboratories, Hsinchu 30078, Taiwan.

PMID: 30913744
DOI: 10.1166/jnn.2019.16494

Abstract

A high-quality HfGeO_x interfacial layer (IL) was formed in a HfO₂/Al₂O₃/HfO₂/GeO_x gate stack through thermal annealing. The diffusing of GeO into the HfO₂ layer led to the mixing of the GeO_x and HfO₂ layers, as identified through energy-dispersive X-ray Spectroscopy (EDX). X-ray photo-electron spectroscopy (XPS) data for HfGeO_x IL confirmed the formation of Ge-O-Hf bonds owing to the induced shift of the Ge3d^ox spectra to lower binding energies. The electrical and reliability data indicated that the capacitor with HfGeO_x IL presented not only lower interface states density (Dit, approximately 7 × 10¹¹ eV^-1cm^-2) but also less Dit increment (approximately 3 × 10¹¹ eV^-1cm^-2) after stressing than did the capacitor without the HfGeO_x IL. Moreover, the Ge p-metal-oxide-semiconductor field-effect transistor HfGeO_x IL exhibited a high effective hole mobility (approximately 704 cm2/V s).