Light extraction enhancement by the fabrication of sub-micron structures on GaN-based LEDs

A cost effective and high throughput imprinting technique is integrated to conventional light emitting diodes (LEDs) chip process to enhance the light extraction efficiency. Sub-micron surface texture composed of spin on glass (SOG) is directly imprinting onto the top of transparent conductive layer (TCL). The electrical performances of LED chips are not damaged after applying the sub-micron structure. Compared to LED chips without SOG cover layer, the light extraction efficiency enhancements are 27.6% and 4.8% for LED chips with two dimensional (2D) hole-array and a planar SOG.