Excellent uniformity on large diameter GaN on silicon LED wafer

We report on the crystal quality and on‐wafer device performance of GaN‐on‐Si LED wafers grown by metalorganic chemical vapour deposition on Si(111) substrates. Average XRD FWHM of 343 arcsec and 456 arcsec for the 002 and 102 reflections, respectively, are measured for GaN‐on‐Si template wafers and a dislocation density around 5×108 cm–2 is determined via etch pit density. Excellent electroluminescence uniformity for the 150 and 200 mm blue LED wafers was achieved. The standard deviation values measured across the wafer surface are 3.9% for the electroluminescence intensity, 0.6–0.8% for the peak wavelength and 1.3% for the forward voltage. The high uniformity confirms the viability of the GaN‐on‐Si technology on large substrate diameters for next generation LED manufacturing. The feasibility of a two‐step growth process for LED wafers on GaN‐on‐Si templates is demonstrated successfully and the issues of wafer to wafer uniformity and processing yield are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)