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因蓝宝石具有良好的稳定性能,且其生产技术成熟,是目前异质外延GaN应用最广泛的衬底材料之一。采用图形化蓝宝石衬底技术可以降低GaN外延层材料的位错密度,提高LED的内量子效率,同时提高LED出光效率提高,近年来引起了国内外的广泛关注。概述了图形化蓝宝石衬底的研究进展,包括图形化蓝宝石衬底的制备工艺、图形尺寸、图形形状及图形化蓝宝石衬底的作用机理;详细介绍了凹槽状、圆孔状、圆锥形、梯形和半球状5种图形形状,并分析了GaN材料在不同图形形状的图形化蓝宝石衬底上的生长机理及不同图形形状对GaN基LED器件性能的影响。对图形化蓝宝石衬底技术的研究方向进行了展望,提出了亟待研究和解决的问题。
Because sapphire has good stability and its production technology is mature, it is one of the most widely used substrate materials for heteroepitaxial GaN. The use of the patterned sapphire substrate technology can reduce the dislocation density of the GaN epitaxial layer material, improve the internal quantum efficiency of the LED, and improve the LED light-emitting efficiency, attracting wide attention at home and abroad in recent years. The research progress of graphitized sapphire substrate is summarized, including the preparation process, the size of the pattern, the shape of the pattern and the action mechanism of the patterned sapphire substrate. The effects of groove shape, circular hole shape, conical shape, Trapezoidal and hemispherical five kinds of shapes, and analyzed the growth mechanism of GaN materials on the patterned sapphire substrate with different shapes and the influence of different shapes on the performance of GaN-based LED devices. The research direction of the graphic sapphire substrate technology is prospected, and the problems that need to be studied and solved are put forward.