MAIN BODY SWITCH TYPE SOI(SILICON-ON-INSULATOR) CIRCUIT AND METHOD OF FORMING THE SAME

摘要

PURPOSE: A threshold voltage of an FET element is increased after switched from a floating state to a biased state by changing a bulk CMOS element to an element within a silicon substrate on an insulator. CONSTITUTION: A unit cell (1) includes an SOINMOS transistor (60), and its main body or an isolated SOI substrate region (62) is connected to main-body-device transistor switches (64 and 66). The switch (64) is connected to a reference signal (74). When operated by a control signal (80) applied to a gate (78), the switch (64) supplies the signal (74) to the main body (62) of the transistor (60). The main body (62) is connected to a reference signal (76) via a switch (66), and the switch (66) is operated by a control signal (84) supplied to a gate (80). In an active switching state, the threshold voltage level is low, and in a standby state, it is high.