THREE-DIMENSIONAL SIMULATION FOR NEGATIVE RESISTANCE CHARACTERISTICS OF PARASITIC BIPOLAR TRANSISTOR IN A SMALL-SIZED MOSFET STRUCTURE

摘要

The behaviours of parasitic bipolar transistors are investigated by exploring the physical mechanisms of negative resistance characteristics generated in a small-sized MOSFET structure. Physical experiments and three-dimensional simulations verify the expected negative resistance characteristics. The effects of variations of device parameters such as injected substrate current levels, doping concentrations, channel widths, and physical device sizes are investigated by simulation. According to simulation results, the operation of a parasitic bipolar transistor is initiated by the injected substrate current; this explains the negative resistance characteristics occurring at low operating voltages.