Ultrathin zirconium silicate films deposited on Si(100) using Zr(O(i)-Pr)(2)(thd)(2), Si(O(t)-Bu)(2)(thd)(2), and nitric oxide

Abstract

Ultrathin Zr silicate films were deposited using Zr(Oi-Pr)(2)(tetramethylheptanedione,thd)(2), Si(O(t)-Bu)(2)(thd)(2) and nitric oxide in a pulse-mode metallorganic chemical-vapor deposition apparatus with a liquid injection source. High resolution transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), and medium energy ion scattering were employed to investigate the structure, surface roughness, chemical state, and composition of the films. The nitric oxide used as oxidizing gas, instead of O(2), not only reduced the thickness of the interfacial layer but also removed the carbon contamination effectively from the bulk of the films. The as-deposited Zr silicate films with a Si: Zr ratio of 1.3:1 were amorphous, with an amorphous interfacial layer 0.3-0.6 nm thick. After a spike anneal in oxygen and a 60 s nitrogen anneal at 850degreesC, these films remained amorphous throughout without phase separation, but the interfacial layer increased in thickness. No evidence of Zr-C and Zr-Si bonds were found in the films by XPS and carbon concentrations <0.1 atom %, the detection limit, were obtained. The hysteresis, fixed charge density, and leakage current determined from capacitance-voltage analysis improved significantly after postdeposition anneals at 850 degrees C and the films exhibited promising characteristics for deep submicrometer metal-oxide-semiconductor devices. (C) 2003 The Electrochemical Society.