In-situ deposited HfO 2 and Y 2 O 3 on epi-Si/p-Ge—a comparative study of the interfacial properties and reliability

• Published in: Japanese Journal of Applied Physics Vol. 61; no. SC; p. SC1074
• Main Authors: Chu, Tien-Yu, Wan, Hsien-Wen, Cheng, Yi-Ting, Cheng, Chao-Kai, Hong, Yu-Jie, Kwo, Jueinai, Hong, Minghwei
• Format: Journal Article
• Language: English
• Published: 01.05.2022
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/ac51e6

Abstract Single-crystal Si films six-monolayers in thickness were epitaxially grown on Ge(001) surface to minimize the formation of undesirable GeO x with subsequent deposition of HfO 2 and Y 2 O 3 . The interfacial properties and reliability of the in-situ deposited high- κ oxides on epi -Si/ p -Ge(001) were compared. We have achieved interface trap density ( D it ) values of (1–3) × 10 11 eV −1 cm −2 in the Y 2 O 3 / epi -Si/ p -Ge(001), which are two times lower than those of the HfO 2 / epi -Si/ p -Ge(001). The capacitance-equivalent-thicknesses under different annealing conditions were extracted to analyze the interdiffusion in the gate stacks under various thermal treatments. Y 2 O 3 / epi -Si/Ge exhibited higher thermal stability than HfO 2 / epi -Si/Ge. In both high- κ ’s gate stacks, the effective charge sheet densities (Δ N eff ) are lower than the targeted value of 3 × 10 10 cm −2 . Compared to the Y 2 O 3 gate stacks, attainment of a high acceleration factor of 11 in the HfO 2 gate stacks suggested an improved defect-carrier decoupling in the latter stacks.