High-Gain Lateral Bipolar Action in a Mosfet Structure

A hybrid-mode device based on a standard submicrometer CMOS technology is presented. The device is essentially a MOSFET in which the gate and the well are internally connected to form the base of a lateral bipolar junction transistor (BJT). At low collector current levels, lateral bipolar action with a current gain higher than 1000 is achieved. No additional processing steps are needed to obtain the BJT when the MOSFET is properly designed, n-p-n BJT's with a 0.25-pm base width have been successfully fabricated in a p-well 0.25-pm bulk n-MOSFET process. The electrical characteristics of the n-MOSFET and the lateral n-p-n BJT at room and liquid nitrogen temperatures will be reported. © 1991 IEEE