SIMULATION OF THE LATERAL ELECTRICAL-FIELD FOR THE ANALYSIS OF THRESHOLD VOLTAGE INSTABILITIES OF SUSPENDED-GATE FIELD-EFFECT TRANSISTORS

The adsorption at the open insulator surface under the air gap of susp ended-gate field-effect transistors (SGFETs), which leads to mobile ch arges, and their redistribution due to lateral electrical field streng ths are two of the reasons for the threshold voltage instability of th ese gas sensors. A two-dimensional computer simulation has been carrie d out to determine the lateral electrical field in the device, especia lly in the gate insulator area. The evaluation of the modelling result s has led to useful conclusions about the design optimization of the s ensor and its operating conditions.