AVS 50th International Symposium
    High-k Gate Dielectrics and Devices Topical Conference Tuesday Sessions
       Session DI-TuM

Paper DI-TuM3
Characteristics of High-k Gate Dielectric Formed by Oxidation of Sputtered Hf/Zr/Hf Thin Fims on the Si Substrate

Tuesday, November 4, 2003, 9:00 am, Room 317

Session: High-k Dielectric Growth and Processing
Presenter: Y. Roh, Sungkyunkwan University, Korea
Authors: H.-D. Kim, Sungkyunkwan University, Korea
Y. Roh, Sungkyunkwan University, Korea
N.-E. Lee, Sungkyunkwan University, Korea
C.-W. Yang, Sungkyunkwan University, Korea
Correspondent: Click to Email
Recently, high-k gate oxide have been extensively investigated to overcome the problems such as large leakage current caused by the direct tunneling through extremely thin SiO@sub 2@. We previously demonstrated that simple oxidation of sputtered Hf thin films on Si results in HfO@sub 2@HfSi@sub x@O@sub y@ stacked high-k gate oxides simultaneously with excellent physical and electrical properties; negligible hysteresis, excellent EOT value (1.2 nm) and low leakage current (2 X 10@super -3@ A/cm@super 2@ at 1.5 V after compensating the flatband voltage). In this work, we further investigated the characteristics of high-k gate dielectric formed by the oxidation of Hf/Zr/Hf film (1.5 nm) deposited on the Si substrate by a sputtering method. The oxidation and annealing were performed at 500~800 °C for 60~120 min under O@sub 2@ ambient and at 500~900 °C for 30~60 min under N@sub 2@ ambient, respectively, in furnace. To form MOS capacitors, Pd gate was thermally evaporated on the HfO@sub 2@ film using a shadow mask with circular dots. We found that the electrical properties of MOS devices with oxidized Hf/Zr/Hf film are further improved as compared to those obtained after oxidizing single Hf film with same thickness (i.e., 1.5 nm) In addition to the negligible hysteresis, we obtained the EOT value of 1.15 nm and the leakage current density of 4.2 X 10@super -3@ A/cm@super 2@ at -3 V. More importantly, the deterioration of high-k gate oxide caused by high-temperature oxidation and/or annealing processes drastically minimized. For example, even after the 900 °C oxidation of Hf/Zr/Hf film, EOT and leakage current density were 1.37 nm and 2.78 X 10@super -6@ A/cm@super 2@ at -3 V, respectively. We speculate that this improvement is due to the minimization of undesirable SiO@sub 2@ formation between High-k oxide and Si. These results, as well as further investigation of physical properties of the samples using XPS, will be presented at the conference.