| 초록 |
Although HfO2 and ZrO2 high-k materials as alternatives for conventional SiO2 gate dielectric are promising candidates today, atomic oxygen (O) fast diffuses through these films. Thus interfacial layers are formed when depositing ZrO2 and HfO2 directly on Si, respectively. For these reasons silicates of zirconium (Zr) and hafnium (Hf) are promising dielectric materials with demonstrated thermal stability in direct contact with Si. Zr-silicate films were deposited by CVD using Zr(NEt2)4/Si(OCH3(CH2)3)4 precursors. Hf(NEt2)4/ Si(OCH3(CH2)3)4 precursors were used to grow Hf-silicate films. The permittivity of the films was about 8-17 at 8-30nm thickness. The film composition was confirmed by XPS and AES results. In high-resolution TEM images and FE-SEM images, Hf silicate-Si interface was seen to be atomically sharp, but Zr silicate-Si interface has very thin native oxide. The film was completely amorphous up to high temperature (800-900℃), which was confirmed by thin film-XRD. I-V and C-V curves of silicate films were measured from -4 V to 4V applied voltage with an Al electrode. supported by a grant No.(R01-2002-000-00279-0(2002)) from Korea Science & Engineering Foundation. |
