High-voltage DMOS and PMOS in analog IC's

A lateral 300V DMOS device is described which can be integrated in a standard bipolar IC process. The device, applicable as a high voltage source follower for analog circuits, is based upon the "double-acting resurf" principle; a modification with an interrupted p- top layer or with a stepped field plate is used. The p- layer improves the interconnection-induced breakdown and can be used in the extended drain of a 280 V PMOST.