MOVPE growth of high-quality Al0.1Ga0.9N on Si(111) substrates for UV-LEDs

We have investigated the growth parameters of AlN seeding and buffer layers to improve the crystalline quality of Al0.1Ga0.9N on Si (111) substrates. We present the dependence of AlN seeding layer growth conditions using X‐ray diffraction (XRD) and atomic force microscopy measurements to achieve high‐quality Al0.1Ga0.9N growth. To further improve the Al0.1Ga0.9N quality, AlN‐based superlattices (SLs) with different growth temperatures were introduced as buffer layers. With the optimized growth parameters of AlN seeding layers and AlN‐based SLs, best FWHMs of XRD ω‐scans around the (0002) reflection of 540 arcsec and 1400 arcsec for the (10‐10) reflection were achieved for a ∼1‐μm‐thick Al0.1Ga0.9N layer. FE‐SEM and TEM measurements show that the optimized high temperature‐AlN/low temperature‐AlN SL buffer layers were able to act as dislocation filters for high‐quality Al0.1Ga0.9N growth. In addition, Cathodoluminecence measurements showed near‐bandgap luminescence peaks of Al0.1Ga0.9N with high intensity and narrow linewidth. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)