EBSD measurement of strains in GaAs due to oxidation of buried AlGaAs layers

• Published in: Microelectronic engineering 2004-07, Vol.75 (1), p.96-102
• Main Authors: Keller, R.R, Roshko, A, Geiss, R.H, Bertness, K.A, Quinn, T.P
• Format: Article
• Language: English
• Subjects: Applied sciences; EBSD; Electronics; Exact sciences and technology; Interfaces; Materials; Microelectronic fabrication (materials and surfaces technology); Oxidation; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Strain; Testing, measurement, noise and reliability
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2003.11.010

We have characterized elastic strain fields associated with the wet-thermal oxidation of buried Al x Ga 1− x As ( x∼0.98) layers of thickness 80 nm, situated between GaAs layers of thickness 200 nm, on a GaAs substrate. The compressive strains accompanying oxidation can exceed 6% and may lead to interlayer delamination or fracture. Automated electron backscatter diffraction measurements were performed about individual oxide growth fronts on longitudinally cross-sectioned samples. We found that the elastic strain fields can be detected and mapped with a spatial resolution of better than 30 nm, using pattern sharpness quantification. Measured strain fields are elongated along the interfaces and extend approximately 1 μm around the growth front. We present efforts to quantify the spatial extent of these strain fields, as well as finite element simulations of the mechanics of oxide formation in this structure.