Low Power and Low Voltage MOSFETs with Variable Threshold Voltage Controlled by Back-Bias

摘要

We have studied the characteristic trade-offs in low power and low voltage MOSFETs from the viewpoint of back--gate control and body effect factor. Previously reported MOSFET structures are classified into four categories in terms of back-gate structures. It is shown that a MOSFET with a fixed back-bias has only a limited current drive at low voltage ir- respective of device structures, while current drive of a dynamic threshold MOSFET with body tied to gate is more enhanced with increasing body effect factor. We have proposed a new dynamic threshold MOSFET, electrically induced body (EIB) DTMOS, which has a very large body effect factor at low threshold voltage and high current drive at low supply voltage.