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-MoP7
Characteristics of HfO@sub 2@/HfSi@sub x@O@sub y@ Film as an Alternative Gate Dielectric in Metal-Oxide-Semiconductor Devices

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

Session: High K Dielectrics Poster Session
Presenter: H. Kang, Sungkyunkwan University, Korea
Authors: H. Kang, Sungkyunkwan University, Korea
Y. Roh, Sungkyunkwan University, Korea
G. Bae, Sungkyunkwan University, Korea
D. Jung, Sungkyunkwan University, Korea
C.-W. Yang, Sungkyunkwan University, Korea
Correspondent: Click to Email
Recently, research efforts on high-k gate oxides have been focused on materials such as HfO@sub 2@, ZrO@sub 2@, and their silicates due to their excellent electrical properties. In particular, the HfO@sub 2@/HfSi@sub x@O@sub y@ gate-oxide produces the excellent interfacial properties between HfSi@sub x@O@sub y@ and Si, while the effective dielectric constant can be further increased by forming the HfO@sub 2@ layer on HfSi@sub x@O@sub y@. In this work, we investigated the physical and electrical properties of the HfO@sub 2@/HfSi@sub x@O@sub y@ prepared by a simple method; that is, the oxidation of sputtered Hf metal films on Si followed by N@sub 2@ annealing. Thin Hf layers were directly deposited on Si substrate by sputtering. The oxidation and annealing were performed at 500 °C for 120 min and in N@sub 2@ ambient at 500 °C for 60 min in furnace, respectively. Al gate was thermally evaporated on the HfO@sub 2@ film using a shadow mask. Using the TEM, AES, and XPS techniques, we confirmed that the oxidation of the thin Hf films on Si results in a HfO@sub 2@/HfSi@sub x@O@sub y@ stack layer. In addition, the thickness of an amorphous HfSi@sub x@O@sub y@ layer (HfO@sub 2@ layer) reduces (increases) after the post-oxidation annealing in N@sub 2@ ambient, which causes the increase of the effective dielectric constant. The hysteresis window and the interface state density of HfO@sub 2@/HfSi@sub x@O@sub y@ were less than 10 mV and ~3x10@super 11@ /cm@super 2@ eV without PMA, respectively. The leakage current was also low (1x10@super –5@ A/cm@super 2@ at 2 V). It is believed that these excellent results were obtained due to existence of the amorphous HfSi@sub x@O@sub y@ buffer layer. We also found that the degradation of HfO@sub 2@/HfSi@sub x@O@sub y@ gate oxides is more severe when electrons were injected from the gate electrode.