R & D to reduce on-resistance by thinning the substrate thickness of SiC diodes is becoming more and more active. This trend is the most prominent among the low and medium voltage products under 1.2kV withstand voltage. The background is that the more a low withstand voltage product is, the thinner the drift layer is to be deposited on the substrate, and therefore the larger the proportion of the resistance component of the substrate is in the on-resistance of the SiC diode. At present, the thickness of SiC substrate to 350μm for the mainstream, ultra-thin products have to reach about 230μm. In order to further reduce the thickness, many large SiC power component manufacturers are committed to the relevant research and development. For example, Rohm thinned the SiC substrate to 50 μm by a grinding process and used it to manufacture a SiC Schottky barrier diode (SBD) with a withstand voltage of 700V. On the occasion of ICSCRM 2013 ("ICSCRM2013", held from September 29 to October 4, 2013), the company compared the on-resistance of the prototype SBD with that of an SBD of the same breakdown voltage fabricated using a 230 μm-thick substrate value. The on-resistance of a 50 μm product is 0.22 mΩcm2, which is reduced to less than half the 0.48 mΩcm2 of a 230 μm product. Mitsubishi Electric also uses a 90μm thick SiC substrate prototype 1.2kV SiCSBD voltage. The company has published relevant results at ICSCRM2013. Although no specific on-resistance values ​​have been disclosed, the on-resistance is reduced by 0.4 mΩcm2 compared to the same breakdown voltage SBD fabricated using a substrate about 300 μm thick. In addition, Infineon is also working on the development of SiC diodes using thin SiC substrates. The company presented a withstand voltage 650V SiC diode that reduced the substrate to 110μm at the International Society of Power Semiconductor International "ISPSD2013" (Hosted by the Institute of Electrical and Electronics Engineers) held in May 2013.