Discerning the Piezoelectric Quality of CdS Crystals and ZnO Films From Their Etch Properties

ORAL

Abstract

Several tests have been used over the years to determine the quality of piezoelectric crystals and films. A test which has been found especially useful is chemical etching. Chemical etching, while destructive to a portion of the crystal or film, reveals considerable information which can be related to its piezoelectric quality. The characteristics of the etching of CdS and ZnO crystals or films is highly anisotropic depending upon whether the acid attacks the c-axis metal face or sulfide-oxide face, or lateral to the c-axis. The etch pit density per unit area is a useful parameter for both crystals and films and can be used for comparison purposes with piezoelectric related properties. For example by controlling the percentage of the acid etchant in water, direct comparisons can be made of film properties under different deposition conditions. Etch times for ZnO films extend as low as 200 Angstroms per second for high piezoelectric coupling factor films with dense uniform fiber grains and as high as 1000 Angstroms per second for nonuniform grain structures. This paper will present the results of etching studies on (1) crystalline CdS and (2) thin-film ZnO under sputter deposition.

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Authors

  • Fred Hickernell

    University of Arizona

  • Seth Putterman

    Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA, Department of Physics, Arizona State University, Tempe, AZ 85287, USA, College of Optical Sciences, University of Arizona, Colorado State University, University of Virginia, Auburn University, Northern Kentucky University, Utah Valley State College, Brigham Young University, Arizona State University, University of Amsterdam, New Mexico State university, University of Minesota, Pulse Field Facility, NHMFL, LANL, NM, Institute of Physics ASCR , Czech Republic, University of Minesota-Twin City, New Mexico State University, Director, Advanced Photon Source, Argonne National Lab, Australian Synchotron Source, Advanced Photon Source, Argonne National Lab, University of Arizona, U.S. Naval Research Laboratory, Wellesley College, Observatoire de Paris, France, Freie Universitat Berlin, Florida State Univ., Univ. Sci. Tech. China, Iowa State University, Lawrence Livermore National Laboratory, Mahabad Azad University, Carnegie Mellon University, Tempe Preparatory Academy, University of California, Los Angeles