Growth of high quality GaN epilayer on AlInN/GaN/AlInN/GaN multilayer buffer and its device characteristics

The role of AlInN1st/GaN/AlInN2nd/GaN multi‐layer buffer (MLB) on the growth of the high quality GaN epilayers was demonstrated by atomic force microscope (AFM), X‐ray diffraction (XRD), photoluminescence, and Hall measurement. The surface morphology and crystalline quality of GaN epilayers were considerably dependent on AlInN layers thicknesses rather than those of GaN inter layers. With optimal thickness of 2nd AlInN layer, the pit density of GaN epilayers was substantially reduced. Also, the RMS roughness of the well ordered terraces generated on the GaN surface was 1.8 Å at 5 × 5 μm2. The omega‐rocking width of GaN (0002) Bragg peak and Hall mobility of GaN epilayers grown on AlInN1st/GaN/AlInN2nd/GaN MLB were 190 arcsec and 500 cm2/Vs, while those values of GaN epilayers on single GaN buffer layer were 250 arcsec and 250 cm2/Vs, respectively. Especially, the light output power and operating voltage of the fabricated light emitting diodes with this new buffer layer was about 5 mW and 3.1 V (dominant luminous wavelength ∼460 nm) at 20 mA, respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)