Strain-induced step bunching in orientation-controlled GaN on Si

• Published in: Japanese Journal of Applied Physics 2016-05, Vol.55 (5S), p.5
• Main Authors: Narita, Tetsuo, Iguchi, Hiroko, Horibuchi, Kayo, Otake, Nobuyuki, Hoshi, Shinichi, Tomita, Kazuyoshi
• Format: Article
• Language: English
• Subjects: Aluminum nitride; Bunching; Epitaxial layers; Gallium nitrides; Reflection; Seeds; Silicon; Silicon substrates
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.55.05FB01

We report a technique for the fabrication of high-quality GaN-on-silicon (Si) substrates for use in various power applications. GaN epitaxial layers were generated on Si(111) vicinal faces that had been previously covered with a thin coating of Al2O3 to control the orientation of the AlN seed layers. We obtained orientation-controlled GaN layers and found a linear relationship between the GaN c-axis and Si[111] tilt angles. As a result, the threading dislocation density in the AlN seed layer was reduced and high-quality GaN layers were generated. The X-ray rocking curves for these layers exhibited full width at half maximum values of 390′′ and 550′′ for the (004) and (114) reflections, respectively. Significant step bunching was observed on a GaN(0001) vicinal face produced using this technique, attributed to strain-induced attractive interactions between steps. Thus, by controlling the strain near the surface layer, we achieved the step flow growth of GaN on Si.