Development of n-type epitaxial growth on 200 mm 4H-SiC wafers for the next generation of power devices

Abstract

Driven by the spread of electric vehicles, the market for SiC power devices is expanding so rapidly that many suppliers are struggling to meet the customer's demand both in terms of final devices and raw material, which nowadays consists of SiC wafers with a diameter of 150 mm (6 in.). STMicroelectronics (ST), world leader in the sale of SiC power device, has reacted by starting the in-house production of the next-generation wafers with a diameter of 200 mm (8 in.). This work describes the optimization of the n-type 4H-SiC epilayers on 200 mm substrates performed by ST in collaboration with LPE® “an ASM company” (LPE). The density of defects and the thickness and doping uniformity of the epilayers grown on 200 mm substrates are characterized, showing results comparable to the ones obtained for standard 150 mm wafers. Also, the reproducibility of the manufacturing process is improved, resulting in a run-to-run variation of the epilayer's thickness and doping below 2%.