Modeling and simulation study of AC characteristics of an NMOS based High Pressure Sensor

In this paper a 0.5 μm NMOS device is used as a High Pressure Sensor by incorporating a Tungsten metal gate (which acts as a Pressure sensing Diaphragm as well) and 1-Mender based serpentine spring at four corner, in a conventional NMOS device. The device is capable of measuring pressures in the range of 10-205 MPa. The sensor, also being a FET device, was also investigated for its AC domain Characteristics. The small signal voltage gain is found to increase with increase in applied pressure, which is verified from PSpice simulations and mathematical Modeling. The frequency response of the Pressure Sensitive Insulated Gate Field Effect Transistor (PSIGFET) is also obtained for different applied pressure. The device shows almost linear increment in the cut-off frequency with increase in applied pressure, with maximum cut-off frequency of 27.71 GHz at a pressure of 170 MPa, whereas the cut of frequency of normal NMOS device of similar dimension being 18 GHz only.