C-Axis Oriented HZO on Flat Amorphous TiN Achieving High Uniformity, Breakdown Field, Final 2Pr, and Endurance
Journal
IEEE Transactions on Electron Devices
Journal Volume
72
Journal Issue
1
Start Page
222
End Page
227
ISSN
0018-9383
1557-9646
Date Issued
2025-01
Author(s)
Zefu Zhao
Yu-Tsung Liao
Yu-Rui Chen
Yun-Wen Chen
Wan-Hsuan Hsieh
Jer-Fu Wang
Yu-An Chen
Hao-Yi Lu
Wei-Teng Hsu
Dai-Ying Lee
Ming-Hsiu Lee
Abstract
Metal-ferroelectric-metal (MFM) capacitors with flat amorphous TiN are demonstrated to achieve the c-axis of orthorhombic phase (o-phase) well-aligned along the deposition direction, uniform electric field, negligible fatigue, and a high remanent polarization (2Pr) of 62μ C/cm2. The large lattice misfit between crystalline TiN and Hf0.5Zr0.5O2 (HZO) creates a larger barrier to form the o-phase HZO as compared to the amorphous TiN underlayer. Using chemical-mechanical polishing (CMP) can obtain a 0.3 nm roughness flat TiN, measured by atomic force microscopy (AFM). HZO on flat amorphous TiN exhibits a uniform and high breakdown field (EBD) of 4.8/-5.1 MV/cm for positive/negative voltage. A flat TiN mitigates the formation of oxygen vacancies (Vo) as compared to the rough TiN due to the weak and uniform electric field with few local extremes in HZO. After 4E12 endurance cycles, the HZO on the flat TiN exhibits a high final 2Pr of 56μ C/cm2 due to small dipole pinning by Vo2+. This work demonstrates the way to achieve uniformly high 2Pr, large EBD, and high endurance by the flat amorphous TiN.
SDGs
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Type
journal article