Metalorganic chemical vapor deposition of titanium oxide for microelectronics applications

Abstract

A chemical vapor deposition process has been developed for titanium dioxide (TiOx) for applications as capacitor dielectric in sub-quarter-micron dynamic random-access memory devices, and as gate insulators in emerging generations of etal-oxide-semiconductor transistors. Studies using the β-diketonate source precursor (2,2,6,6-tetramethyl-3,5-heptanedionato) titanium were carried out to examine the underlying mechanisms that control film nucleation and growth kinetics and to establish the effects of key process parameters on film purity, composition, texture, morphology, and electrical properties. Resulting film properties were thoroughly analyzed by x-ray diffraction, x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, scanning electron microscopy (SEM), focused-ion-beam SEM, and capacitance–voltage (C–V) measurements. The study resulted in the identification of an optimized process for the deposition of an anatase–rutile TiOx film with a dielectric constant approximately 85 at 1 MHz for a 330-nm thickness, and a leakage current below 2 × 10−8 A/cm2 for bias voltage values up to 3.5 V.