AVS 47th International Symposium
    Dielectrics Wednesday Sessions
       Session DI+EL+MS-WeA

Paper DI+EL+MS-WeA4
Chemical and Microstructural Separation of Homogeneous Plasma Deposited (ZrO@sub2@)@subx@(SiO@sub2@)@sub(1-x)@ films (x @<=@ 0.5) into SiO@sub2@ and ZrO@sub2@ Phases after Rapid Thermal Annealing in Ar at 900°C

Wednesday, October 4, 2000, 3:00 pm, Room 312

Session: Alternate Gate Dielectrics
Presenter: B. Rayner, North Carolina State University
Authors: B. Rayner, North Carolina State University
R. Therrien, North Carolina State University
G. Lucovsky, North Carolina State University
Correspondent: Click to Email
Zr-silicate alloys along the pseudo-binary join from SiO@sub2@ to ZrO@sub2@ have attracted interest as high-k dielectrics for Si CMOS devices with equivalent oxide thickness extending to 0.6 nm. In this study alloy films were deposited on HF-last and pre-oxidized and/or nitridized Si(100) by remote plasma enhanced chemical vapor deposition using Zr(IV)-t-butoxide. Film and interface chemical composition, local atomic bonding, and film morphology were studied by Auger electron spectroscopy, Fourier transform infrared absorption, X-ray diffraction, and Rutherford back-scattering. These studies identified two alloy regimes: (i) SiO@sub2@-rich compositions to the compound silicate, ZrSiO@sub4@ (x = 0.5), where properties may be suitable for high-k applications, e.g., films are amorphous on deposition and remain so up to at least 800°C, and (ii) ZrO@sub2@-rich compositions in which films are either partially or totally crystalline on deposition, or after relatively low temperature (< 600°C) anneals. Alloys in the SiO@sub2@-rich regime are chemically-ordered as-deposited at ~350°C with predominantly Si-O-Si and Zr-O-Si bonds, but after annealing in Ar at 900°C for 60 s, separate chemically and microstructurally into SiO@sub2@ and ZrO@sub2@ phases. The ZrO@sub2@ phase is crystalline at the ZrSiO@sub4@ composition. This separation may limit integration of these films into devices which incorporate polycrystlline-Si gate electrodes requiring dopant activation at temperatures > 900°C. Capacitance-voltage and current-voltage characteristics will be presented for as-deposited and annealed films to illustrate the effects of chemical phase separation and crystallization in defining maximum post deposition processing temperatures.