Nonresonant detection of terahertz radiation by silicon-on-insulator MOSFETs

The detection of subterahertz (200 GHz) radiation by silicon-on-insulator MOSFETs with submicron gate lengths in the temperature range from ∼8 to 350 K is reported. The photoresponse measured against gate voltage exhibited a maximum near the threshold voltage with the amplitude decreasing with decreasing temperature. The photoresponse reached the maximum at the gate bias close to the threshold voltage and increased with an increase of the drain-to-source current. This behaviour agrees with the mechanism linking the photoresponse to the excitation of the overdamped plasma waves in the transistor channel. The observed effect could be used for non-destructive, contactless testing of silicon very large integrated circuits in situ.