Latticemisorientation at domain boundaries in beta-Ga2O3 single-crystal substrates observed via synchrotron radiation X-ray diffraction imaging and X-ray reticulography

To evaluate the lattice misorientation at domain boundaries (DBs) in beta-Ga2O3, we performed X-ray diffraction imaging (XRDI), X-ray reticulography (XRR), and X-ray topography (XRT) using a synchrotron radiation light source. Four reciprocal lattice vectors (g-vectors) were applied, and the DBs showed different visibilities in the XRDI maps depending on the g-vector. By analyzing possible characteristics of the misorientation, the XRDI results suggested that the DB being investigated was associated with a misorientation on the ((10) over bar 05) plane and contained twist and tilt components. The apparent peak change in XRDI caused by the two components was calculated. We further succeeded in separating the tilt and twist components usingXRRimages in conjunction with simulation. Dislocation arrays at the DBs were observed using XRT, and the average distance between the dislocations in the array was consistent with the misorientation obtained using XRDI and XRR. The distribution of DBs across a wide area was acquired by a combination of XRR images recorded on a charge-coupled device camera and X-ray films. The fringe-patterned XRR on X-ray films provided a powerful and nondestructive tool to characterize DBs distributed across a largediameter wafer with an angular resolution on the order of several arc sec (low 10(-5) rad).