Plasma-enhanced flexible metal-insulator-metal capacitor using high-k ZrO(2) film as gate dielectric with improved reliability

Abstract

We demonstrate a new flexible metal-insulator-metal capacitor using 9.5-nm-thick ZrO(2) film on a plastic polyimide substrate based on a simple and low-cost sal-gel precursor spin-coating process. The surface morphology of the ZrO(2) film was investigated using scan electron microscope and atomic force microscope. The as-deposited ZrO(2) film under suitable treatment of oxygen (O(2)) plasma and then subsequent annealing at 250 degrees C exhibits superior low leakage current density of 9.0 x 10(-9) A/cm(2) at applied voltage of 5 V and maximum capacitance density of 13.3 fF/mu m(2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when we employed O(2) plasma at relatively low temperature and power (30 W), hence enhancing the electrical performance of the capacitor. The shift (Zr 3d from 184.1 eV to 184.64 eV) in X-ray photoelectron spectroscopy of the binding energy of the electrons towards higher binding energy; clearly indicates that the O(2) plasma reaction was most effective process for the complete oxidation of the sol-gel precursor at relatively low processing temperature. (C) 2010 Elsevier Ltd. All rights reserved.