Reduction of epitaxial defects on 4°-off 4H-SiC homo-epitaxial growth by optimizing in-situ etching process

摘要

The investigations of in-situ etching of 4H-SiC epi-growth on 4° off-axis 100 mm diameter substrates under different conditions have been carried out in a commercial warm-wall multi-wafer planetary reactor. The surface morphologies of the as-etched substrates have been characterized by atomic force microscopy on 20 × 20 μm~2. Based on the step height and roughness mean square, the best etching condition for 4H-SiC 4° off-axis substrates was determined to be H2 + HCl at 1500 ℃ for 10 min. With the optimized in-situ etching process, high quality 4H-SiC epitaxial layers with excellent surface morphology have been obtained, and the defect density is lowered to 0.45 cm~(-2) resulting in a projected 2×2 mm die yield of ～98%.