Growth and characterization of pendeo-epitaxial GaN ( 1 1 2 ¯ 0 ) on 4H–SiC ( 1 1 2 ¯ 0 ) substrates

• Published in: Journal of crystal growth 2006-05, Vol.290 (2), p.504-512
• Main Authors: Wagner, B.P., Reitmeier, Z.J., Park, J.S., Bachelor, D., Zakharov, D.N., Liliental-Weber, Z., Davis, R.F.
• Format: Article
• Language: English
• Subjects: A1. Atomic force microscopy, A1. Crystal morphology; A1. Surfaces; A3. Metalorganic chemical vapor deposition; A3. Pendeo-epitaxy; B1. Nitrides; B2. Semiconducting III–V materials; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2006.02.011

Growth on AlN/4H–SiC ( 1 1 2 ¯ 0 ) substrates of coalesced, non-polar GaN ( 1 1 2 ¯ 0 ) films having volumes of material with reduced densities of dislocations and stacking faults has been achieved from etched stripes via the statistical and experimental determination of the effect of temperature and V/III ratio on the lateral and vertical growth rates of the GaN{0 0 0 1} faces combined with pendeo-epitaxy. AFM of the uncoalesced GaN(0 0 0 1) and GaN ( 0 0 0 1 ¯ ) vertical faces revealed growth steps with some steps terminating at dislocations on the former and a pitted surface without growth steps, indicative of decomposition, on the latter. Coalescence was achieved via (a) a two-step route and the parameters of (1) T = 1100 ° C and V / III = 1323 for 40 min and (2) 1020 °C and V / III = 660 for 40 min and (b) a one-step route that employed T = 1020 ° C and a V/III ratio = 660 for 6 h. The densities of dislocations in the GaN grown vertically over and laterally from the ( 1 1 2 ¯ 0 ) stripes were ∼4×10 10 cm −2 and ∼2×10 8 cm −2, respectively; the densities of stacking fault in these volumes were ∼1×10 6 cm −1 and ∼2×10 4 cm −1, respectively. The defects in the wing material were observed primarily at the bottom of the film where lateral growth of the GaN occurred from the AlN and the SiC. Plan view AFM also revealed different microstructures and a reduction in the RMS roughness values from 1.2 to 0.95 nm in these respective regions.