Growth of crack‐free high‐quality GaN on Si(111) using a low‐temperature AlN interlayer: observation of tilted domain structures in the AlN interlayer

Abstract

We report on the growth of crack-free high-quality GaN layers on Si(111) using a low-temperature AlN interlayer (LT-AlN IL) between GaN epilayers by ultrahigh vacuum chemical vapor deposition. The use of a thin LT-AlN IL resulted in the complete elimination of cracks and significant improvements in structural and optical properties of the GaN layer. The GaN epilayer containing the LT-AlN IL exhibited a strong band-edge emission with the line width of 26.5 meV at room-temperature. Additional distinct domains with a tilt angle of ±0.9° in the LT-AlN IL, found by synchrotron X-ray diffraction, are believed to play a key role in the effective relaxation of thermal stress and the reduction of threading dislocations.

Structural and optical characterization of GaN epilayers grown on Si(111) substrates by hydride vapor-phase epitaxy

“…Extensive defects and even dense microcracks may be generated in GaN layers on the silicon substrate. These defects and cracks act as nonradiative and scattering centers for light propagation and electron transport [7,8]. The density of cracks and defects need to be reduced to achieve acceptable device performance and reliability.…”