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In this report we were able to successfully identify and localize in 3D 3C and 6H foreign polytypes and stress in the embedded epilayer by high resolution 3D Raman spectroscopy, that were otherwise invisible under the microscope or SEM, in non-contact and non-destructive way. Stripe patterned deep trenches with aspect ratio about 2 (depth=3.0μm; width=1.5μm) were formed on 4H-SiC substrate by ICP. The epitaxial layer was embedded in these trenches by SiC CVD. Poly type defects and stress in the embedded epilayer were mapped by curve-fitting of spectra obtained from Raman measurement of the embedded SiC epilayer. The location of the foreign polytypes and the stress inside the stripe pattern allows speculating on the origin of the defects and correlating it to the manufacturing process.

In this work, we analyze residual stress on 4H-SiC with Raman spectroscopy that excitation wavelength is deep ultraviolet (DUV) laser 266nm. The residual stress area is created by Vickers Hardness test technique and the area is measured by 2D DUV Raman map. The result is different from visible light excited Raman, because DUV light penetration is shallower than visible light. DUV Raman signal has exactly brings only the sample surface information. We present the advantage of DUV excited Raman to analyze sample surface.