| Stability of Sputtered Hf-Silicate Films in Poly Si/Hf-Silicate Gate Stack Under the Chemical Vapor Deposition of Poly Si and by Annealing |
| Sung-Kwan Kang, Robert Sinclair, Dae-Hong Ko1 |
School of Material Science and Engineering, Stanford University
1Department of Ceramic Engineering, Yonsei University |
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| ABSTRACT |
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We investigated the effects of SiH$_4$ gas on the surface of Hf-silicate films during the deposition of polycrystalline (poly) Si films and the thermal stability of sputtered Hf-silicate films in poly Si/Hf-silicate structure by using High Resolution Transmission Electron Microscopy (HR-TEM) and X-ray Photoelectron Spectroscopy (XPS). Hf-silicate films were deposited by using DC-mag-netron sputtering with Hf target and Si target and poly Si films were deposited at 600$^{circ}C$ by using Low Pressure Chemical Vapor Deposition (LPCVD) with SiH$_4$ gas. After poly Si film deposition at 600$^{circ}C$, Hf silicide layer was observed between poly Si and Hf-silicate films due to the reaction between active SiH$_4$ gas and Hf-silicate films. After annealing at 900$^{circ}C$, Hf silicide, formed during the deposition of poly Si, changed to Hf-silicate and the phase separation of the silicate was not observed. In addition, the Hf-silicate films remain amorphous phase. |
| Key words:
Hf-silicate films, High k dielectric, Poly Si, Thermal stability, Integration |
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