Terahertz detection in MOS-FET: a new model by the self-mixing

High frequency detection based on MOS-FET technology was long justified using a mechanism described by the plasma wave detection theory. In this paper we propose a new model based on the self-mixing process, taking place not in the channel, but in the depleted portion of the transistor body. Hydrodynamic semiconductor equations are solved in the small signal approximation. As a result, we present the dependence of the rectified voltage on the bias gate voltage, which fits carefully several experimental literature results.