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Experimental determination of critical thickness limitations of (010) β-(AlxGa1−x)2O3 heteroepitaxial films.
- Source :
- Applied Physics Letters; 11/27/2023, Vol. 123 Issue 22, p1-7, 7p
- Publication Year :
- 2023
-
Abstract
- The effect of heteroepitaxial β-(Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> film thickness and Al content on surface morphology was characterized to experimentally determine the critical thickness limitations of the (010) β-(Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript>/Ga<subscript>2</subscript>O<subscript>3</subscript> heterostructure. High-resolution x-ray diffraction was used to assess the strain state of the films; reciprocal space mapping (RSM) revealed that even cracked films were still fully strained. In cracked films, diffuse scattering was observed in RSMs, indicating lattice tilting. Cracking of the films was investigated using atomic force microscopy (AFM), x-ray topography (XRT), bright-field scanning transmission electron microscopy (BF-STEM), and high-resolution transmission electron microscopy. Using both AFM and XRT, the [001] direction was observed to be the most prevalent crack direction; however, cracks were also observed in the [100] direction. In uncracked regions of the films, XRT revealed the alignment of threading dislocations along the [001] direction. Cross-sectional imaging of the crack geometry and propagation was performed using BF-STEM, and it was observed that the cracks in the [001] direction extended through the thickness of the β-(Al<subscript>x</subscript>Ga<subscript>1−x</subscript>)<subscript>2</subscript>O<subscript>3</subscript> film (∼205 nm) and a further ∼100–200 nm into the β-Ga<subscript>2</subscript>O<subscript>3</subscript> substrate. Experimental data for critical film thickness showed good agreement with previous theoretical calculations based on the Griffith criterion for crack propagation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00036951
- Volume :
- 123
- Issue :
- 22
- Database :
- Complementary Index
- Journal :
- Applied Physics Letters
- Publication Type :
- Academic Journal
- Accession number :
- 173977231
- Full Text :
- https://doi.org/10.1063/5.0174682