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Growth and Characterization of (La,Sr)(Al,Ta)O 3 Single Crystals: a Promising Substrate for GaN Epitaxial Growth
Author(s) -
Sakowska H.,
Swirkowicz M.,
Mazur K.,
Lukasiewicz T.,
Witek A.
Publication year - 2001
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/1521-4079(200110)36:8/10<851::aid-crat851>3.0.co;2-n
Subject(s) - materials science , epitaxy , transmission electron microscopy , electron microprobe , thermal expansion , substrate (aquarium) , crystallography , characterization (materials science) , microprobe , analytical chemistry (journal) , mineralogy , chemistry , nanotechnology , composite material , metallurgy , oceanography , layer (electronics) , chromatography , geology
Experimental results on the growth and characterization of single crystals of mixed perovskite (La,Sr)(Al,Ta)O 3 (LSAT), a promising material to prepare substrates for GaN epitaxial layers, growth by the Czochralski method, are reported. The single crystals obtained along <111> orientation up to 20 mm in diameter and 50 mm in length were free of inclusions and macroscopic defects. The optical transmission was measured in the region 200 nm – 3000 nm. For the of <111> oriented LSAT single crystals, its measured unit cell parameter ( a = 7.730 Å) matches well to the GaN lattice. The chemical composition was checked by electron microprobe analysis. It was found that it is close to the stoichiometric one. With Lang transmission topography growth striations and dislocations were examined. Data on Vickers microhardness, thermal expansion coefficient, etch pit density and temperature dependence of electrical conductivity and capacitance are reported.