IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Dielectrics Monday Sessions
       Session DI1-MoP

Paper DI1-MoP6
Physical and Electrical Characteristics of W-TiN/HfO@sub 2@/Si (MOS) Devices

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: High K Dielectrics Poster Session
Presenter: S. Yang, Sungkyunkwan University, Korea
Authors: S. Yang, Sungkyunkwan University, Korea
K. Roh, Sungkyunkwan University, Korea
H. Kang, Sungkyunkwan University, Korea
Y. Roh, Sungkyunkwan University, Korea
K. Kim, Sungkyunkwan University, Korea
N.-E. Lee, Sungkyunkwan University, Korea
Correspondent: Click to Email
Recently, the metal/high-k oxide structures have been investigated extensively to implement sub-100 nm MOSFETs technology. In this work, we present the physical and electrical characteristics of MOS capacitors with HfO@sub 2@ gate dielectric and W/TiN gate electrode. The Hf thin films were deposited directly on n-type silicon substrate by a RF magnetron sputtering method. The HfO@sub 2@ films with thicknesses of 6-7 nm were formed by a thermal oxidation of Hf thin film in O@sub 2@ ambient at 500 °C for 120 min in furnace. The annealing of the HfO@sub 2@ films was then carried out in N@sub 2@ ambient at 500 °C for 60 min in furnace. TiN films (30 nm) were deposited on HfO@sub 2@ by a DC reactive sputtering method followed by W deposition (200 nm) using LPCVD. For some samples, only the W films were deposited on HfO@sub 2@ films to investigate the roles of the TiN films. The sheet resistance of W/TiN was ~ 4 @ohm@/square. The intermediate layer between gate dielectric and Si was observed by TEM, which is believed to be a hafnium silicate (HfSi@sub x@O@sub y@) layer. To evaluate the EOT and leakage current characteristics, the C-V and I-V measurements of MOS capacitors with different gate electrode (i.e., W/TiN, W and Pt gate) were performed. The hysteresis of W/TiN gate was negligible (<10 mV) in contrast to that of the Pt gate devices which showed a high value of the hysteresis (>100 mV) due to gate dielectric damage during sputtering deposition. The EOT of W/TiN/HfO@sub 2@ MOS capacitors was 1.9 nm based on the C-V measurement. In addition, as compared to the results obtained from the W/HfO@sub 2@/Si MOS structures, the W/TiN/HfO@sub 2@/Si MOS capacitors showed an excellent current-voltage characteristics: The leakage current was ~2x10@super -5@ A/cm@super 2@ at 2 V which is lower than published results reported by other researchers at the same EOT.