A CMOS integrated circuit containing an isolated n-channel DEMOS transistor and an isolated vertical PNP transistor has deep n-type wells and surrounding shallow n-type wells providing isolation from the p-type substrate. The isolated n-channel DEMOS transistor has an upper n-type layer providing an extended drain, and a lower p-type layer isolating the extended drain from the underlying deep n-type well. The isolated vertical PNP transistor has an upper n-type layer providing a base and a lower p-type layer providing a collector. A CMOS integrated circuit having opposite polarities of the transistors may be formed by appropriate reversals in dopant types.