Towards industrialisation of GaN‐on‐Si based high brightness blue LEDs

Abstract

The manufacturability of blue LED structures grown on 6‐inch Si (111) substrates is reported. The totally epi‐structure thickness is only 3.75 μm, which allows faster epitaxy process throughput and lower manufacturing costs. Well controlled strain engineering leads to a room temperature wafer bow of 0 ± 5 μm and a highly uniform photoluminescence wavelength standard deviation of 1.1 nm. XRD FWHM (002) and (102) are 380 and 390 arcsec, respectively. For a blue 1×1 mm2 vertical thin film die with silicone dome lens, the optical light output power of 563 mW at an operating voltage of 3.05 V is achieved at 350 mA. Excellent leakage current (IR) yield is achieved with over 95% of dies exhibiting IR < 0.1 μA at ‐5 V. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Enhanced optical output of GaN-based near-ultraviolet light-emitting diodes using an ultra-thin air cavity nanopatterned sapphire substrate

“…This seriously limits the external quantum efficiency (EQE) of GaN-based NUV LEDs. Various methods such as buffer layer technology, [9][10][11] flip-chip structure, 12 patterned sapphire substrates (PSSs), [13][14][15] surface roughening, 16,17 photonic crystals [18][19][20] and nanorod structures 21 have been utilized to improve the performance of light-emitting diodes (LEDs). Among these technologies, flipchip structure and PSSs have been successfully applied in commercial GaN-based NUV LEDs.…”

Curvature evolution of 200 mm diameter GaN-on-insulator wafer fabricated through metalorganic chemical vapor deposition and bonding

“…4) The mature substrate removal and bonding technologies are also explored extensively to open new avenues in advanced device options in discrete GaN-on-Si devices. [5][6][7][8] Often, the device orientation in the as-grown Ga-polar GaN-on-Si can be modified by wafer bonding to realize N-polar HEMTs and flip-chip LEDs. This is made possible by the flip-chip bonding of the as-grown Ga-polar devices to a handle Si wafer followed by a removal of the original Si(111) substrate and some parts of the GaN and its Al x Ga 1-x N/AlN buffer layers to expose the device layers.…”