Wafer warpage, crystal bending and interface properties of 4H-SiC epi-wafers

The relationship between the warpage of 4H-SiC CVD grown epi-wafers with crystal bending and substrate properties is investigated. The wafer surface preparation before and after epitaxy is found to affect both long range properties such as the wafer flatness and to some extent local properties such as the epi-substrate interface. Structural characterisation is carried out using X-ray diffraction techniques and KOH etching.