Strain Field in GaAs/GaN Wafer-Bonding Interface and Its Microstructure

The strain fields in a wafer-bonded GaAs/GaN structure are measured by electron backscatter diffraction (EBSD). Image quality (IQ) of EBSD Kikuchi patterns and rotation angles of crystal lattices as strain sensitive parameters are employed to characterize the distortion and the rotation of crystal lattices in the GaAs--interface--GaN structure, as well as to display the strain fields. The results indicate that the influence region of the strains in the wafer-bonded GaAs/GaN structure is mainly located in GaAs side because the strength of GaAs is weaker than that of GaN. The cross-sectional image of transmission electron microscopy (TEM) further reveals the distortion and the rotation of crystal lattices induced by strains systematically.