21.4: Deposition Conditions and HRTEM Characterization of CAAC IGZO

Abstract

Crystallinity and texture of c‐axis aligned crystal indium gallium zinc oxide (CAAC IGZO) films deposited by RF reactive sputtering were studied and characterized over a range of deposition conditions. The characteristic CAAC (009) peak at 2θ=30° was observed by X‐ray diffraction, and nanocrystalline domain texture was determined using a general area detector diffraction system (GADDS). Highly ordered CAAC films were obtained near the InGaZnO 4 composition at a substrate temperature of 310°C and in 10% O 2 . High‐resolution transmission electron microscopy (HRTEM) confirmed the formation of CAAC showing 2‐3 nm domains aligned over 15 nm x 15 nm fields of view. Cross‐section HRTEM of the CAAC/substrate interface shows formation of an initially disordered IGZO layer prior to CAAC formation, suggesting a nucleation mechanism similar to ZnO thin films.