Quantitative Analysis of Dislocations in 4H-SiC Wafers Using Synchrotron X-Ray Topography with Ultra-High Angular Resolution

The wide band gap semiconductor, 4H-SiC, is a promising material for high-power and high-temperature devices due to its outstanding physical properties. Unlike Silicon, defects in 4H-SiC still cannot be completely eliminated even using the latest crystal growth techniques. These defects can be detrimental to the devices and it is important to investigate their properties. The non-destructive characterization technique, X-ray topography (XRT), has been developed over several decades and widely applied to study the crystallographic features of various materials. The utilization of a Si (331) beam conditioner together with a Si (111) double-crystal monochromator (DCM) enables the angular resolution of XRT to be increased by an order of magnitude compared to grazing incidence topography (GIT) or back reflection topography conducted with the DCM alone. This improved technique with extremely small beam divergence is referred to as synchrotron X-ray plane-wave topography (SXPWT). In this study, we will show that the rocking curve width of 4H-SiC 0008 in PWT is only 2.5ʹʹ and thus the lattice distortion at the scale of 1ʹʹ will significantly affect the diffracted intensity. Herein, we report the ultra-high angular resolution in SXPWT enables the detailed probe of the lattice distortion outside the dislocation core in 4H-SiC where the sign of the Burgers vector can be readily determined (Fig. 1). Additionally, dynamical theory of X-ray diffraction was applied to calculate the rocking curve (reflectivity) in SXPWT, and the ray tracing simulation was modified accordingly to calculate the dislocation images under any diffraction conditions. Figure 1