(Invited) Synchrotron White-Beam X-Ray Topography Analysis of the Defect Structure of HVPE-GaN Substrates

Abstract

The defect structure of HVPE-GaN crystals are examined using synchrotron white-beam X-ray topography (SWXRT) and topography results are interpreted and discussed in comparison to reciprocal lattice point broadening from high resolution X-ray diffraction (HRXRD) measurements. Two as-received commercial HVPE-GaN wafers from two different vendors and one HVPE-GaN which was grown on an ammonothermal GaN-seed are investigated in this study. From large-area topography the formation of a cellular defect network is identified for the commercial HVPE-GaN. Large differences in the crystal lattice misorientation deformation (mosaicity) are determined for the different samples by transmission section topography. For the HVPE-GaN grown on an ammonothermal GaN-seed a very low defect density was ascertained. From the contrasts of the topography threading screw-type dislocations and threading mixed-type dislocations were identified. The structure analyses show that the outstanding structural properties of the ammonothermal GaN-seed are adopted by the HVPE-GaN.

Challenges and future perspectives in HVPE-GaN growth on ammonothermal GaN seeds

“…Lutz Kirste analyzed two commercially available HVPE-GaN wafers crystallized on foreign substrates and F-S HVPE-GaN grown before on an Am-GaN seed [45,46]. Rocking curves for two examined reflections were the narrowest in case of F-S HVPE-GaN from Am-GaN seed.…”

(Invited) Growth and Characterization of Bulk HVPE-GaN – Pathway to Highly Conductive and Semi-Insulating GaN Substrates

“…Kirste et al (28,29) analyzed two commercially available F-S HVPE-GaN wafers crystallized on foreign substrates and F-S HVPE-GaN grown before on Am-GaN seed. Rocking curves for examined reflections were the narrowest in the case of GaN from Am-GaN seed.…”