Atomic layer deposition of ZrO2 on W for metal-insulator-metal capacitor application

A metal-insulator-metal (MIM) capacitor using ZrO2 on tungsten (W) metal bottom electrode was demonstrated and characterized in this letter. Both ZrO2 and W metal were synthesized by an atomic layer deposition (ALD) method. High-quality 110similar to115 Angstrom ZrO2 films were grown uniformly on ALD W using ZrCl4 and H2O precursors at 300 degreesC, and polycrystalline ZrO2 in the ALD regime could be obtained. A 13similar to14-Angstrom-thick interfacial layer between ZrO2 and W was observed after fabrication, and it was identified as WOx through angle-resolved x-ray photoelectron spectroscopy analysis with wet chemical etching. The apparent equivalent oxide thickness was 20similar to21 Angstrom. An effective dielectric constant of 22similar to25 including an interfacial WOx layer was obtained by measuring capacitance and thickness of MIM capacitors with Pt top electrodes. High capacitance per area (16similar to17 fF/mum(2)) and low leakage current (10(-7) A/cm(2) at +/-1 V) were achieved. (C) 2003 American Institute of Physics.