Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 46: Focus Session: AlGaN Materials for UV Emitters

HL 46.4: Topical Talk

Wednesday, March 28, 2012, 11:15–11:45, ER 164

Growth and properties of bulk AlN crystals — •Boris Epelbaum — CrystAl-N GmbH, Dr.-Mack-Straße 77, D - 90762 Fürth

Single-crystalline aluminum nitride is a very promising substrate material for nitride-based optoelectronic devices performing in deep UV spectral range. The feasibility of bulk AlN growth using high-temperature Physical Vapor Transport (PVT) method has been convincingly confirmed during last years, but important crystal quality issues still remain. In this presentation we will show our most recent achievements in growth of bulk AlN crystals and discuss some quality issues:

(i) Specific defects in bulk AlN such as macropipes and localized misoriented domains and their evolution during growth process, (ii) Crystal faceting and boule enlargement within a single growth process. The influence of temperature gradient on growth interface and faceting effects on enlargement and structural quality of crystal rim. (iii) Variations of UV transmission in different crystal areas

Finally high structural quality crack-free bulk AlN crystals up to 40 mm in diameter grown using various polar and semi-polar orientations will be demonstrated.