Compositional variation of AlGaN epitaxial films on 6H-SiC substrates determined by cathodoluminescence.
Författare
Summary, in English
High quality epitaxial films of A(l)xGa(1-x)N, grown on SiC substrates, were investigated using spatially resolved cathodoluminescence (CL), scanning electron microscopy, and atomic force microscopy. A variation in the observed peak energy position of the CL was related to alloy fluctuations. CL was used to reveal relative alloy fluctuations of approximately 1% on a sub-micrometer scale, with a precision difficult to surpass with other available techniques. By correlating data from the different techniques, a model was derived. The main feature of it is an alloy fluctuation on the micrometer scale, seeded during the initial growth and extending through the epitaxial film. These alloy fluctuations seems to be related to terrace steps ( approximate to5 nm in height), formed preferentially at scratches on the SiC surface. This investigation indicates that the initial growth of epitaxial films is critical and structures formed at the beginning of the growth tend to persist throughout the growth. Further, a strain gradient from the SiC interface extending towards the surface, was observed.
Avdelning/ar
Publiceringsår
2002
Språk
Engelska
Publikation/Tidskrift/Serie
MRS Internet Journal of Nitride Semiconductor Research
Volym
7
Issue
5
Fulltext
- Available as PDF - 293 kB
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Dokumenttyp
Artikel i tidskrift
Förlag
Materials Research Society
Ämne
- Condensed Matter Physics
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1092-5783