In comparison to pn junction isolation ICs, dielectric isolation ICs have several advantages such as high blocking voltage, small isolation area, high thermal resistance and small interferences among integrated devices, which result in small chip area, multi high output power and floating electric source operation in Dielectrically Isolated High Voltage large electric capacity Power ICs (DI- HVPICs). In this paper, our series of R&Ds for Si DI-HVPICs with the above advantages are introduced in almost time series. On the other hand, SiC semiconductor gets along with the DI-HVPICs in its physical properties and is expected synergistic effects in SiC DI-HVPICs. However, since physical and electrical deference between SiC and Si result in several difficulties in the design of device structure and production process. SiC DI-HVPIC has been investigated in detail and a few solutions have been found, thus conceptual design of 1200 V · 65 A output devices and one chip inverter SiC DI-HVPIC of 600 V·25 kW class for brushless motors have been attempted, and its rough chip size has been estimated. © 2022 The Institute of Electrical Engineers of Japan.