Characterization of reactively sputtered c-axis aligned nanocrystalline InGaZnO4

Crystallinity and texturing of RF sputtered c-axis aligned crystal InGaZnO4 (CAAC IGZO) thin films were quantified using X-ray diffraction techniques. Above 190 degrees C, nanocrystalline films with an X-ray peak at 2 theta = 30 degrees (009 planes) developed with increasing c-axis normal texturing up to 310 degrees C. Under optimal conditions (310 degrees C, 10% O-2), films exhibited a c-axis texture full-width half-maximum of 20 degrees. Cross-sectional high-resolution transmission electron microscopy confirmed these results, showing alignment variation of +/- 9 degrees over a 15 x 15 nm field of view and indicating formation of much larger aligned domains than previously reported. At higher deposition temperatures, c-axis alignment was gradually lost as polycrystalline films developed. (C) 2014 AIP Publishing LLC.