6H-SiC Ion Sensitive Field Effect Transistor Based pH-Meter Study

摘要

In pH-sensing, Ion Sensitive Field Effect Transistors (ISFETs) are novel. Furthermore, Silicon carbide is known to be an interesting semiconductor for high temperature, high frequency and high power applications. Hence, a 6H-SiC ISFET transistor dedicated to chemical pH measurement is modeled with a MOSFET sub-circuit and its electrical characteristics studied so to be used as a pH sensor. Results are compared to a Si based ISFET. Drain saturation current I_(Dsat), transconductance g_m and I_(ON)/I_(OFF) ratio are found to change linearly with pH. Sensitivity in both cases is determined and compared to show that it is material and electrical dependent. These results show that Si and 6H-SiC ISFETs sensitivity S_(I_(Dsat)) is as high as 38.5 μA/pH and 8 μA/pH, respectively. I_(ON)/I_(OFF) ratio is more than 10~8 for 6H-SiC making this technology very promising for pH sensors.