PREPARATION AND CHARACTERIZATION OF HAFNIUM SILICATE DIELECTRIC LAYERS BY PHOTO-ASSISTED MOCVD USING MIXED PRECURSOR OF Hf(O-t-C₄H₉)₄ AND Si(O-t-C₄H₉)₄

ABSTRACT

Hafnium silicate dielectric layers have been prepared by photo-assisted metal organic chemical vapor deposition (MOCVD) using mixed precursor of Hf(O-t-C₄H₉)₄ and Si(O-t-C₄H₉)₄. Deuterium lamp was used for ultraviolet irradiation source to enhance decomposition of mixed precursor. It was confirmed from X-ray photoelectron spectroscopy (XPS) measurement that hafnium silicate dielectric layers were deposited successfully. The hafnium silicate dielectric layers exhibited improved surface roughness (0.12∼ 0.17 nm) and thermal stability. Electrical characterizations revealed that accumulated capacitance, leakage current and interface trap state density were improved, and these improvements may be caused from effective decomposition of mixed precursor by ultraviolet irradiation.

Keywords:

• Photo-assisted MOCVD
• mixed precursor
• hafnium silicate