Evaluation of New Aminoalkoxide Precursors for Atomic Layer Deposition. Growth of Zirconium Dioxide Thin Films and Reaction Mechanism Studies

Atomic layer deposition (ALD) was used for growing zirconium dioxide (ZrO2) thin films by alternate surface reactions between new aminoalkoxides and water. The zirconium aminoalkoxide precursors were Zr(dmae)4, Zr(dmae)2(OtBu)2, and Zr(dmae)2(OiPr)2 (dmae is dimethylaminoethoxide, [OCH2CH2N(CH3)2]). Films were deposited on soda and borosilicate glass at 190-340 °C. The growth rate increased with elongated Zr precursor pulse possibly due to precursor decomposition. The as-deposited films contained substantial amounts of residual hydrogen. Reaction mechanisms were studied with a quadrupole mass spectrometer (QMS) and a quartz crystal microbalance (QCM) connected to the ALD reactor. The QMS results showed that the precursors decompose at higher temperatures, Zr(dmae)4 making an exception. According to the QCM results, all precursors start to decompose with longer Zr precursor pulses.