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Structural properties of InAlN thin layers for HEMT applications
|Arantxa Vilalta Clemente 1, Marie P. Chauvat 1, Yadira Arroyo-Rojas Dasilva 1, Marie A. Poisson 2, Michael Heuken 3, Christoph Giesen 3, Pierre Ruterana 1|
1. CNRS-ENSICAEN, Boulevard du Maréchal Juin, Caen 14050, France
The InxAl1−xN material system is highly attractive for possible applications in high electron mobility transistor. Heterostructures InAlN/GaN, grown by metal organic chemical vapour deposition (MOCVD), have been investigated by transmission electron microscopy and atomic force microscopy and X-ray diffraction for determination of the residual strain. The TEM samples were prepared by standard mechanical polishing and Ar ion beam thinning at 5 KeV and 5° angle incidence. The nominal composition of the investigated samples is around the strain free 0.17% In composition. In these materials where the lattice parameters changes are so steep, the control of the growth parameters is always a challenge. A tight iterative characterisation of the growth process is still necessary in order to optimize it. Observations show that in this instance, in a same growth sequence, the composition of the layers may oscillate between 13-21% In composition. So, the control of the growth parameters is may not be so straightforward.
In this work, we have carried out extensive investigation, by XRD and TEM, of lattice matched AlInN thin and QWs layers grown by MOVPE. We will report on the changes in the structural properties at and around the lattice matched In fraction. The results show that above In=0.2, the MOVPE layers are not only polycrystalline, but also that complete phase separation may take place with XRD detecting pure InN.
The support of the EU under Grant agreement N°: PITN-GA-2008-213238 (RAINBOW project: Initial Training Network of the 7th RTD Framework) is gratefully acknowledged.
Presentation: Poster at E-MRS Fall Meeting 2009, Symposium A, by Arantxa Vilalta Clemente
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-25 17:07 Revised: 2009-06-07 00:48