Epitaxial Si and Gd 2 O 3 Heterostructures - Distributed Bragg Reflectors with Stress Management Function for GaN on Si Light Emitting Devices

• Published in: ECS transactions Vol. 50; no. 4; pp. 47 - 52
• Main Authors: Dargis, Rytis, Clark, Andrew, Arkun, Erdem, Roucka, Radek, Williams, David, Smith, Robin S., Lebby, Michael
• Format: Journal Article
• Language: English
• Published: 15.03.2013
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/05004.0047ecst

Tensile stress in GaN layers grown directly on Si is a serious obstacle for the implementation of this technology for electronic and photonic devices. The problem can be solved by stress engineering using epitaxial buffer layers grown on a Si-substrate. Heteroepitaxial Si and Gd2O3 multilayer structures that can be used both as a tensile strain compensating buffer for GaN epitaxial layers and an efficient reflector for light emitting devices are demonstrated in this work. A three-periods distributed Bragg reflector has been fabricated. It exhibits 82% reflectivity at the design wavelength of 450 nm. In situ curvature measurements of the 200 mm diameter wafers with the grown structure reveal compressive stress in the Gd2O3 -Si multilayer structure. The compressive stress compensates the tensile stress which arises during subsequent growth and cooling of the GaN layer.