Effects of patterned ion implanted sapphire substrate for LED

Light‐emitting diodes (LEDs) were fabricated on patterned ion implanted sapphire substrates using metal organic chemical vapor deposition. The crystal quality of the u‐GaN and n‐GaN epilayers grown on the patterned N+‐ion implanted sapphire substrate was improved compared to that of the u‐GaN and n‐GaN epilayers grown on a conventional sapphire substrate. The optical properties of the u‐GaN and n‐GaN epilayers grown on the patterned ion implanted sapphire substrate were also improved. The light intensity of the LED at 100mA on the patterned ion implanted sapphire chip was up to 78% higher than that of the conventional LED chip according to the quick test on the wafer. The increase in the light intensity is due to the relaxation of the misfit strain at high temperature and the contribution of the internal free energies to the enhancement of structural and optical prop‐ erties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)