Metalorganic chemical vapor phase epitaxy of crack-free GaN on Si (111) exceeding 1 mu m in thickness

We present a simple method for the elimination of cracks in GaN layers grow n on Si (111). Cracking of GaN on Si usually occurs due to large lattice an d thermal mismatch of GaN and Si when layer thicknesses exceeds approximate ly l mum. By introducing thin, low-temperature AIN interlayers, we could si gnificantly reduce the crack density of the GaN layer. The crack density is practically reduced to zero from an original crack density of 240 mm(-2) c orresponding to crack-free regions of 3 x 10(-3) mm(2). Additionally for th e GaN layer with low temperature interlayers, the full width at half maximu m X-ray (20 (2) over bar 24) rocking curve is improved from approximately 2 70 to 65 arcsec.