The GaN-Based Light Emitting Diode Grown on Nanopattern Sapphire Substrate Prepared by Inductively Coupled Plasma Etching

Abstract

We applied nanoimprint lithography to fabricate nanopattern sapphire substrate. Because the imprint resin cannot endure the inductively coupled plasma bombardment, we use Ni metal to replace the resin as our etching mask. And then, we tuned the parameters to achieve a depth-enough nanopattern sapphire substrate (200-500-nm thick). Then, light emitting diode (LED) structures were grown and the quality was characterized by X-ray diffraction and photoluminescence. The LED tester and integrating sphere were used to analyze the device property. The results could demonstrate that the film quality was improved with increasing etching depth. And, the compressive strain was also released with increasing etching depth. In addition, increasing etching depth could not only improve internal quantum efficiency, but also improve light extraction efficiency. Thus, the external quantum efficiency was enhanced. These evidences demonstrated that nanopatterned sapphire with deeper depth certainly enhanced performance of LEDs.Index Terms-Etching rate, GaN, inductively coupled plasma (ICP), selectivity.

The improvement of GaN-based LED grown on concave nano-pattern sapphire substrate with SiO2 blocking layer

“…In our previous study [11], we observed that PSS can improve not only the LEE but also the IQE of the resultant devices. The growth mechanism and GaN properties of nanometer-scale patterns remain incompletely understood.…”

“…Cl-based inductively coupled plasma (ICP) was used to etch out the NPSS with a depth of 500 nm. Details of the ICP parameters are provided in our previous report [11]. After etching, SiO 2 deposition was performed to cover the sidewalls and bottoms of the etched holes [profile in Fig.…”