Strain evolution in high temperature AlN buffer layers for HVPE-GaN growth
2002 (English)In: Physica status solidi. A, Applied research, ISSN 0031-8965, Vol. 190, no 1, 59-64 p.Article in journal (Refereed) Published
High temperature AlN buffer layers are deposited on a-plane sapphire by reactive magnetron sputtering. The effect of the buffer thickness on the AlN structural properties and surface morphology are studied in correlation with the subsequent hydride vapour phase epitaxy of GaN. A minimum degree of mosaicity and screw dislocation density is determined for a 50 nm thick AlN buffer. With increasing the AlN thickness, a strain relaxation occurs as a result of misfit dislocation generation and higher degree of mosaicity. A blue shift of the E-1(TO) frequency evaluated by means of infrared reflection spectroscopy is linearly correlated with an increase in biaxial compressive stress in the films through the IR stress factor k(E1)(b) = 2.57 +/- 0.26 cm(-1) GPa(-1).
Place, publisher, year, edition, pages
2002. Vol. 190, no 1, 59-64 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-48172OAI: oai:DiVA.org:liu-48172DiVA: diva2:269068