Cross-sectional stress distribution in AlxGa1-xN heterostructure on Si(111) substrate characterized by ion beam layer removal method and precession electron diffraction. (15th September 2016)

• Record Type: Journal Article
• Authors: Reisinger, M.; Zalesak, J.; Daniel, R.; Tomberger, M.; Weiss, J.K.; Darbal, A.D.; Petrenec, M.; Zechner, J.; Daumiller, I.; Ecker, W.; Sartory, B.; Keckes, J.
• Is Part Of: Materials & design. Volume 106(2016)
• Page Start: 476
• Page End: 481
• Publication Date: 2016-09-15
• Subjects: Heterostructure -- Residual stress -- Ion beam layer removal method -- GaN -- FIB -- Precession electron diffraction; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.06.001
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: A residual stress depth gradient is characterized in a 1.8 μm thick AlN/Al0.25 Ga0.75 N/GaN/Al0.22 Ga0.78 N heteroepitaxial structure grown using metallic-organic chemical vapour deposition on Si(111) substrate. The cross-sectional stress profile is evaluated with a step of 100 nm using ion beam layer removal (ILR) method based (i) on a sequential focused ion beam milling of a microcantilever, (ii) on an evaluation of a cantilever bending after every milling step and (iii) on a stress profile recalculation using finite element simulation. The profile shows tensile stress of ~ 1.5 GPa in AlN nucleation layer, stress changing from compressive to tensile in Al0.25 Ga0.75 N and GaN sublayers and relatively small stresses below 100 MPa in the top Al0.22 Ga0.72 N sublayer. The stress profile is qualitatively correlated with the results from precession electron diffraction which indicates approximately the same stress behavior. The cross-sectional stress magnitude and variation are interpreted by the mismatches of lattice constants and coefficients of thermal expansion as well as by growth mode changes during Al0.25 Ga0.75 N and GaN sublayer formation. The approach demonstrates the possibility to resolve nanoscale variation of residual stresses in heteroepitaxial structures using ILR method. Graphical abstract: Highlights: Ion Beam Layer Removal (ILR) characterization of stresses in heteroepitaxial thin film Precession electron diffraction characterization of Alx Ga1-x N heterostructure Nonlinear stress gradient in Alx Ga1-x N heterostructure