We report pulsed atomic layer epitaxy growth of a very high crystalline quality, thick (∼2 μm) and crack-free AlN material on c-plane sapphire substrates via a sandwich method using metal organic chemical vapor deposition. This sandwich method involves the introduction of a relatively low temperature (1050 °C) 1500 nm thick AlN layer between two 250 nm thick AlN layers which are grown at higher temperature (1170 °C). The surface morphology and crystalline quality remarkably improve using this sandwich method. A 2 μm thick AlN layer was realized with 33 arcsec and 136 arcsec full width at half maximum values for symmetric and asymmetric reflections of ω-scan, respectively, and it has an atomic force microscopy root-mean-square surface roughness of ∼0.71 nm for a 5 × 5 μm2 surface area.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films