Effects of BCl3 addition on Ar/Cl2 gas in inductively coupled plasmas for lead zirconate titanate etching

The lead zirconate titanate (PbZrxTi1-xO3:PZT) ferroelectric thin films have received great attention for the applications on nonvolatile memory, infrared sensor, electro-optical device, microelectromechanical system device, etc. In order to accomplish the integration of these devices, the etching process for both PZT film and electrode material must be developed. In this study, PZT etching was performed using planar inductively coupled Ar(20)/Cl-2/BCl3 plasma. The etch rate of PZT film was 2450 Angstrom/min at Ar(20)/BCl3 (80) gas mixing ratio and substrate temperature of 80 degrees C. X-ray photoelectron spectroscopy analysis for film composition was utilized. The chemical bond of PbO is broken by ion bombardment, and the peak of metal Pb in a Pb 4f peak begins to appear upon etching, decreasing Pb content faster than Zr and Ti. Also, the relative content of oxygen decreases rapidly. We thought that abundant B and BCl radicals made a volatile oxycompound such as BxOy and/or BCl-O bond. To understand the etching mechanism, Langmuir probe and optical emission spectroscopy analysis were utilized for plasma diagnostic: (C) 2000 American Vacuum Society. [S0734-2101(00)00404-8].