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Mapping strain gradients in the FIB-structured InGaN/GaN multilayered films with 3D X-ray microbeam
- Source :
-
Materials Science & Engineering: A . Nov2010, Vol. 528 Issue 1, p52-57. 6p. - Publication Year :
- 2010
-
Abstract
- Abstract: This research presents a combined experimental-modeling study of lattice rotations and deviatoric strain gradients induced by focused-ion beam (FIB) milling in nitride heterostructures. 3D X-ray polychromatic microdiffraction (PXM) is used to map the local lattice orientation distribution in FIB-structured areas. Results are discussed in connection with microphotoluminescence (μ-PL), fluorescent analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) data. It is demonstrated that FIB-milling causes both direct and indirect damage to the InGaN/GaN layers. In films subjected to direct ion beam impact, a narrow amorphidized top layer is formed. Near the milling area, FIB-induced stress relaxation and formation of complicated 3D strain fields are observed. The resulting lattice orientation changes are found to correlate with a decrease and/or loss of PL intensity, and agree well with finite element simulations of the three-dimensional strain fields near the relaxed trenches. Experimentally, it is found that the lattice surface normal has an in-plane rotation, which only appears in simulations when the GaN-substrate lattice mismatch annihilates the InGaN-substrate mismatch. This behavior further supports the notion that the film/substrate interface is incoherent. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 09215093
- Volume :
- 528
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Materials Science & Engineering: A
- Publication Type :
- Academic Journal
- Accession number :
- 54607354
- Full Text :
- https://doi.org/10.1016/j.msea.2010.04.045