GaN-based optoelectronics on silicon substrates

Cracking of GaN on Si usually occurs due to the large thermal mismatch of GaN and Si when layer thicknesses exceed approximately 1 μm in metalorganic chemical vapor deposition (MOCVD) preventing the realization of device-quality material. The thermal stress can be reduced significantly by a combination of different concepts such as the insertion of low-temperature AlN interlayers, introducing multiple AlGaN/GaN interlayers, and growing on prepatterned substrates. The growth of crack-free GaN-based light emitting diodes (LEDs) on silicon on patterned Si(111) with areas of 100 μm×100 μm is reported