Improving interfacial and electrical properties of HfO2/SiO2/p-Si stacks with N2-plasma-treated SiO2 interfacial layer
The effect of N2-plasma-treated SiO2 interfacial layer on the interfacial and electrical characteristics of HfO2/SiO2/p-Si stacks grown by atomic layer deposition (ALD) was investigated. The microstructure and interfacial chemical bonding configuration of the HfO2/SiO2/Si stacks were also examined by high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Compared with the samples without N2-plasma treatment, it is found that the samples with N2-plasma treatment have less oxygen vacancy density for SiO2 interfacial layer and better HfO2/SiO2 interface. In agreement with XPS analyses, electrical measurements of the samples with N2-plasma treatment show better interfacial quality, including lower interface-state density (D it, 9.3 × 1011 cm−2·eV−1 near midgap) and lower oxide-charge density (Q ox, 2.5 × 1012 cm−2), than those of the samples without N2-plasma treatment. Additionally, the samples with N2-plasma treatment have better electrical performances, including higher saturation capacitance density (1.49 μF·cm−2) and lower leakage current density (3.2 × 10−6 A·cm−2 at V g = V fb − 1 V). Furthermore, constant voltage stress was applied on the gate electrode to investigate the reliability of these samples. It shows that the samples with N2-plasma treatment have better electrical stability than the samples without N2-plasma treatment.
KeywordsMetal–oxide–semiconductor High-k Atomic layer deposited N2-plasma treatment Interfacial characteristic Reliability
This study was financially supported by the National Science and Technology Major Project of China (No. 2013ZX02303-001-002).
- Triyoso DH, Hegde RI, Gregory R, Spencer G, Schaeffer JK, Raymond M. Factors impacting stabilization of tetragonal phase in HfxZr1-xO2 high-k dielectrics. In: Proceedings of the 2009 IEEE International Conference on IC Design and Technology; 2009. 89.Google Scholar
- Park J, Park TJ, Cho M, Kim SK, Hong SH, Kim JH, Seo M, Hwang CS, Won JY, Jeong R, Choi JH. Influence of the oxygen concentration of atomic-layer-deposited HfO2 gate dielectric films on the electron mobility of polycrystalline-Si gate transistors. J Appl Phys. 2006;99(9):094501.CrossRefGoogle Scholar
- Wu Y, Lucovsky G, Lee YM. The performance and reliability of PMOSFET’s with ultrathin silicon nitride/oxide stacked gate dielectrics with nitrided Si-SiO2 interfaces prepared by remote plasma enhanced CVD and post-deposition rapid thermal annealing. IEEE Trans Electron Devices. 2000;47(7):1361.CrossRefGoogle Scholar
- Hauser JR, Ahmed K. Characterization of Ultra-Thin Oxides Using Electrical C-V and I-V Measurements. AIP Conference Proceedings. 1998;449(1):235.Google Scholar