ABSTRACT
Hafnium-based dielectrics have been extensively investigated as a possible replacement for SiO2. A novel volatile anhydrous Zr/Hf mixed-metal nitrate precursor ZrxHf1-x(NO3)4(ZHN) was successfully synthesized. ZrxHf1-xO2 thin films were first prepared by the chemical vapor deposition (CVD) technique from the precursor of this mixed-metal nitrate. Differential scanning calorimetry (DSC) and infrared spectra (IR) measurements of ZHN indicated that ZHN may be mixture of single Hf(NO3)4 and a solid solution of Zr(NO3)4 and Hf(NO3)4. The ZrxHf1-xO2 thin films exhibit good dielectric properties with a moderate bandgap value of 5.6 eV and a value for k of 22. ZrxHf1-xO2 is, therefore, a promising candidate for gate-dielectric application, and the anhydrous mixed-metal nitrate can be a potential precursor for high-k materials derived from CVD.
ACKNOWLEDGMENTS
This project was supported by the Program for New Century Excellent Talents in University (NCET-04-0451). It was also supported by the Natural Science Foundation of China and Jiangsu Province (50672036 and BK2006122) and a grant from the State Key Program for Basic Research of China.