Nondestructive quantitative mapping of impurities and point defects in thin films: Ga and VZn in ZnO:Ga

Ga-doped ZnO (GZO) films grown by pulsed-laser deposition on quartz and other lattice-mismatched substrates can routinely attain resistivities of 2 x 10(-4) Omega.cm and thus compete with Sn-doped In2O3 (ITO) in large-area transparent-electrode applications. Nondestructive, high-resolution (1-mm) maps of thickness d, concentration n, and mobility mu on such films can be obtained automatically from commercial spectroscopic ellipsometers. From n and mu, degenerate-electron scattering theory yields donor N-D and acceptor N-A concentrations at each point. Finally, N-D and N-A can be identified as [Ga] and [V-Zn], respectively, demonstrating high-density mapping of impurities and point defects in a semiconductor thin film. (C) 2014 AIP Publishing LLC.