Investigation on the work function of tungsten and thermal stability of W/SiO2/Si, W/SiON/Si and W/HfO2/Si gate stacks

Pei Chuen Jiang, Jen Sue Chen, K. H. Cheng, T. J. Hu, K. B. Huang, F. S. Lee

研究成果: Conference contribution

摘要

Replacement of poly-Si and SiO2 with new gate electrode and high k gate oxide is an inevitable trend for next-generation CMOS integrated circuits. Therefore, work function (Φm) of gate electrodes as well as the thermal stability and electrical behaviors of MOS capacitors should be understood. In this study, tungsten (W) is applied as the gate electrode and the gate dielectric materials are SiO2, SiON and HfO2. Φ of W and electrical properties of the MOS structures are investigated. Φm,measured of W is calculated from the flat-band voltage (V m,measured) of MOS capacitors with dielectrics of various thicknesse. For W/SiO2/Si structure, the Φm,measured of W is 4.67 V; however, the Φm,measured of W in W/SiON/Si and W/HfO 2/Si structures is 4.60 V and 4.84 V, respectively. The result means that the Φm,measured of W in W/HfO2/Si structures has extrinsic contributions to Fermi level pinning. The phase of as-deposited W is β-W (or β-W+α-W) phase and transfers to α-W+WO3 mix phase after annealing at 500°C in N2+H2 ambient for 30 min. The trapped charges and oxide charges of dielectric are reduced after annealing. However, the EOT of W/SiO2/Si increases significantly after annealing, indicating the thermal stability of this capacitor is poor.

原文English
主出版物標題Gate Stack Scaling
主出版物子標題Materials Selection, Role of Interfaces, and Reliability Implications
頁面167-173
頁數7
出版狀態Published - 2006 十二月 1
事件2006 MRS Spring Meeting - San Francisco, CA, United States
持續時間: 2006 四月 172006 四月 21

出版系列

名字Materials Research Society Symposium Proceedings
917
ISSN(列印)0272-9172

Other

Other2006 MRS Spring Meeting
國家United States
城市San Francisco, CA
期間06-04-1706-04-21

    指紋

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

引用此

Jiang, P. C., Chen, J. S., Cheng, K. H., Hu, T. J., Huang, K. B., & Lee, F. S. (2006). Investigation on the work function of tungsten and thermal stability of W/SiO2/Si, W/SiON/Si and W/HfO2/Si gate stacks. 於 Gate Stack Scaling: Materials Selection, Role of Interfaces, and Reliability Implications (頁 167-173). (Materials Research Society Symposium Proceedings; 卷 917).