Quantitative analysis of dislocations in 4H-SiC wafers using synchrotron X-ray topography with ultra-high angular resolution

Abstract

Utilization of an Si(331) beam conditioner together with an Si(111) double-crystal monochromator (DCM) enables the angular resolution of synchrotron X-ray topography to be increased by an order of magnitude compared with grazing-incidence topography 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). This study demonstrates that the rocking curve width of 4H-SiC 0008 in PWT is only 2.5′′ and thus the lattice distortion at the scale of 1′′ will significantly affect the diffracted intensity. This work reports the ultra-high angular resolution in SXPWT which enables detailed probing of the lattice distortion outside the dislocation core in 4H-SiC, where the sign of the Burgers vector can be readily determined through comparison with ray-tracing simulations.

Analysis of Strain in Ion Implanted 4H-SiC by Fringes Observed in Synchrotron X-Ray Topography

“…If the separation of the fringes is approximated wider than 10", the conventional high-resolution X-ray diffractometry with monochromator can reveal such patterns. Here, we recorded fringes with separation about 2" that can only be revealed from SWPXT since the 0.5" width of the incident beam (determined from DuMond diagrams) can be provided by the asymmetric Si (331) beam conditioner, which acts as an extremely fine probe [8]. With such a fine probe, SWPXT is highly sensitive to lattice distortion.…”

“…Synchrotron X-ray plane wave topography (SXPWT) [8], (previously referred as synchrotron Xray rocking curve topography (SXRCT) [9,10,11]), is capable of measuring strain and tilt of 4H-SiC with a strain sensitivity of the order of 10 -6 . Wieteska, Wierzchowski and coworkers have observed various peaks and fringes in implanted Si and AlxGa1-xAs/GaAs epilayer by SXPWT, which show same angular positions as synchrotron rocking curve with double crystal monochromator [12,13].…”

(Invited) Application of Synchrotron X-Ray Topography Techniques to the Analysis of Defect Microstructures in Bulk GaN Substrates and Epilayers for Power Devices

“…While SMBXT is suitable for imaging of defects, to obtain quantitative information on distribution of lattice strains in a sample, it can be modified by the introduction of a beam conditioner to obtain a highly strain sensitive setup described as SXPWT [3]. This is important for GaN, as lattice strain can be introduced during device fabrication processes which can affect homogeneity and thereby performance of devices.…”