Maximum observable thickness of 4H-SiC crystals by high-voltage scanning transmission electron microscopy

• The thickness of 4H-SiC observable by 1 MV-HVEM is 8.6 μm (STEM) and 5.4 μm (TEM). • Dislocations in a 5 μm-thick crystal can be imaged with a resolution of ∼ 10 nm. • The proposed method has a 10 3 times better spatial resolution than existing methods. • The proposed method will be useful for failure analysis of electronic devices. An experimental method has been demonstrated to evaluate dislocations in 4H-SiC crystals that affect the performance of industrially important power devices. Using high-voltage electron microscopy with 1 MeV electrons, it is possible to visualize dislocations contained in a 5 μm-thick crystal with a spatial resolution of ∼ 10 nm. This method has a 10 3 times better spatial resolution than currently existing characterization methods for crystalline defects in semiconductor wafers. Scanning transmission electron microscopy (STEM) is suitable for imaging thick specimens than transmission electron microscopy (TEM) in respect of image blurring due to chromatic aberration caused by inelastic scattering of electrons with increasing specimen thickness. With the proposed method, the maximum observable specimen thickness was determined to be 8.6 μm for STEM and 5.4 μm for TEM.