Thermodynamic analysis for growth of transition-metal nitride thin films by pulsed laser deposition

摘要

Thermodynamic analysis has been carried out for growth of transition-metal nitride thin films by pulsed laser deposition. TiN films with (200) orientation were grown on Si(100) substrate without any oxide impurity phase formation at substrate temperature in the range of 20 similar to 700 degrees C. However, polycrystalline ZrN films mixed with ZrO2 phase were grown at 550 similar to 700 degrees C at the same deposition conditions. We prepared the diagram of chemical potential of nitrogen (mu(N2)) with variation of temperature for the nitride films and the P-O2-P-N2 phase diagram for Ti and Zr at 973 K. We could expect from the thermodynamic diagram that ZrO2 phase tends to be more easily formed at 700 degrees C than TiO2 phase during the nitride film growth at the same gas atmosphere, as is consistent with experimental results. Formation and phase stability of TiN and ZrN films at elevated temperatures are systematically analyzed and compared to each other.