Semiconductor device and portable electronic apparatus

Abstract

There is provided a semiconductor device of low power consumption and high reliability having DTMOS' and substrate-bias variable transistors, and portable electronic equipment using the semiconductor device. On a semiconductor substrate (), trilayer well regions () are formed, and DTMOS' () and substrate-bias variable transistors () are provided in the shallow well regions (). Large-width device isolation regions () are provided at boundaries forming PNP, NPN or NPNP structures, where a small-width device isolation region () is provided on condition that well regions on both sides are of an identical conductive type. Thus, a plurality of well regions of individual conductive types where substrate-bias variable transistors () of individual conductive types are provided can be made electrically independent of one another, allowing the power consumption to be reduced. Besides, the latch-up phenomenon can be suppressed.