In-situ preparation of Ti-containing Ta_2O_5-films by halide CVD

摘要

Thin films of mixed tantalum and titanium oxide were produced by halide CVD using the metal iodides and oxygen as starting materials. Films with compositions ranging from 5 to 100% titanium were deposited on poly-crystalline silicon at a reactor temperature of 500℃, and the compositions 40-65% titanium at 600℃. The composition was found to have a strong effect on the phase content and the permittivities of the films. Deposition at 500℃ resulted in amorphous films for compositions between 5 and 50% titanium, and crystalline TiO_2 with Ta in solid solution for higher concentrations. For the 500℃ films, the calculated dielectric constants were approximately 35 for amorphous films, and around 60 for samples containing crystalline TiO_2.