Analysis and Design of a CMOS-based Terahertz Sensor and Readout

摘要

The large interest shown in the field of terahertz detectors research by the scientific community brought to the development of several kinds of devices based on different principles. Many, however, have some peculiar characteristics that prevent their use in low-cost or compact equipment, because of cryogenic cooling, or the use of exotic materials, etc.rnRecently, approaches using field-effect transistors exploiting the oscillation of electron density (plasma waves) or the phenomena known as "self-mixing" in RF modulators, allowed to foresee the possibility to employ standard CMOS technologies to build such sensors.rnIn this work we analyze the behavior of this kind of detectors in order to understand how to design an optimized device and then how to exploit it by proper readout. Optimized electromagnetic coupling to the detector has been implemented using a dipole antenna. Electromagnetic simulations together with the developed model allowed calculating a projected noise figure of the detector of 38pW/Hz~(1/2). Two dedicated readout circuits have been designed, one intended to read the detector as a current generator, while the other reads it as a voltage generator. The developed circuits have been designed and sent for fabrication in a standard 0.3 5 μm CMOS technology.