title: Low defect large area semi-polar (11[Formula: see text]2) GaN grown on patterned (113) silicon.
abstract: We report on the growth of semi-polar GaN (11[Formula: see text]2) templates on patterned Si (113) substrates. Trenches were etched in Si (113) using KOH to expose Si {111} sidewalls. Subsequently an AlN layer to prevent meltback etching, an AlGaN layer for stress management, and finally two GaN layers were deposited. Total thicknesses up to 5 [Formula: see text]m were realised without cracks in the layer. Transmission electron microscopy showed that most dislocations propagate along [0001] direction and hence can be covered by overgrowth from the next trench. The defect densities were below [Formula: see text] and stacking fault densities less than 100 cm [Formula: see text]. These numbers are similar to reports on patterned r-plane sapphire. Typical X-ray full width at half maximum (FHWM) were 500" for the asymmetric (00.6) and 450" for the (11.2) reflection. These FHWMs were 50 % broader than reported for patterned r-plane sapphire which is attributed to different defect structures and total thicknesses. The surface roughness shows strong variation on templates. For the final surface roughness the roughness of the sidewalls of the GaN ridges at the time of coalescence are critical.
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Markus
authors.initials: M
authors.lastname: Pristovsek
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Yisong
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Tongtong
authors.initials: T
authors.lastname: Zhu
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Frentrup
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Menno J
authors.initials: MJ
authors.lastname: Kappers
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge27 Charles Babbage Road, Cambridge CB3 0FS, UK.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Humphreys
authors.affiliation: Tyndall National InstituteLee Maltings, Dyke Parade, Cork, Ireland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Kozlowski
authors.affiliation: Tyndall National InstituteLee Maltings, Dyke Parade, Cork, Ireland.
authors.forename: Pleun
authors.initials: P
authors.lastname: Maaskant
authors.affiliation: Tyndall National InstituteLee Maltings, Dyke Parade, Cork, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: Corbett
keywords: MOVPE; growth; patterning; semi-polar GaN; silicon; substrates