Growth of high quality AlN/sapphire templates with high growth rate using a medium-temperature layer. (January 2019)

• Record Type: Journal Article
• Authors: Wu, Hualong; Zhao, Wei; He, Chenguang; Zhang, Kang; He, Longfei; Chen, Zhitao
• Is Part Of: Superlattices and microstructures. Volume 125(2019)
• Page Start: 343
• Page End: 347
• Publication Date: 2019-01
• Subjects: MOCVD -- AlN -- Medium-temperature layer -- High growth rate -- Crack-free; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2018.12.008
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: In this work, crack-free 3.3-μm-thick AlN films with high crystalline quality and atomic smooth surfaces were achieved on sapphire substrates at a high growth rate of 2.9 μm/h. Double-axis x-ray rocking curves showed a full width at half maximum of 315 and 419 arc sec for (0002) and (10 1 ¯ 2) reflections, respectively, corresponding to a total threading dislocation (TD) density of 9.79 × 10 8 cm −2 . Cracks were suppressed and crystalline quality was improved by introducing a medium-temperature (MT) layer. It was found that the density of both screw- and edge-type TDs could be significantly reduced by introducing the MT-AlN layer under appropriate temperature. The crystalline improvement is attributed to the delayed coalescence of the AlN islands and higher probability for the annihilations of TDs by the MT-AlN layer under appropriate temperature. This method provides a promising way in growing practical thick AlN templates suitable for large-scale industrial production. Highlights: High-quality AlN/sapphire templates with high growth rates were grown by MOCVD. Cracks were suppressed by introducing a medium-temperature (MT) AlN layer. Improved crystalline quality was achieved in AlN films with MT-AlN layers. Obvious annihilations of threading dislocations were observed in the MT-AlN region.