MOVPE growth of GaN on Si(1 1 1) substrates

Abstract Metalorganic chemical vapor phase deposition of thick, crack-free GaN on Si can be performed either by patterning of the substrate and selective growth or by low-temperature (LT) AlN interlayers enabling very thick GaN layers. A reduction in dislocation density from 10 10 to 10 9  cm −2 is observed for LT-AlN interlayers which can be further improved using monolayer thick Si x N y in situ masking and subsequent lateral overgrowth. Crack-free AlGaN/GaN transistor structures show high room temperature mobilities of 1590 cm 2 /V s at 6.7×10 12  cm −2 sheet carrier concentration. Thick crack-free light emitters have a maximum output power of 0.42 mW at 498 nm and 20 mA.