Direct liquid injection metallorganic chemical vapor deposition of ZrO2 thin films using Zr(dmae)(4) as a novel precursor

Abstract

A novel liquid Zr precursor with a donor-functionalized alkoxy ligand [Zr(OCH2CH2NMe2)(4),Zr(dmae)(4)] (dmae = dimethylaminoethoxide) has been characterized by thermogravimetry (TG) and differential scanning calorimetry (DSC) analysis, nuclear magnetic resonance, and mass spectrometry. Zr(dmae)(4) vaporizes near 320 degreesC and reacts with oxygen at around 310 degreesC under our TG/DSC measurement conditions. The bond strength of Zr-dmae was found to be similar to that of Zr-(OPr)-Pr-i. The ZrO2 thin films deposited at 300-480 degreesC by a direct liquid injection metallorganic chemical vapor deposition process had a dense and smooth morphology. The film had a weak monoclinic phase in an amorphous background without any other metastable phase such as tetragonal or cubic. The high-frequency (1 MHz) capacitance-voltage curves showed that the flatband voltage (V-FB) of the ZrO2 thin films deposited at 400 degreesC was close to the theoretical value of -0.9 V. The interface trap density near the midgap was found to be less than 1 x 10(11) cm(-2) eV(-1), which was calculated by the Terman method. (C) 2001 The Electrochemical Society.