Reduction of Low Frequency Noise Impact to Terahertz Detectors in CMOS

Variation of low frequency noise including 1/f noise and Lorentzian spectra is the dominant source of variations for noise equivalent power (NEP) of THz detectors using a forward biased diode connected NMOS transistor. Elimination of the impact of low frequency noise variation to NEP with 1-V amplitude AC biasing at 44MHz is demonstrated in 830-GHz detectors using a diode connected PMOS transistor. It should be possible to apply this technique to eliminate the impact of low frequency noise variations in THz NMOS and Schottky diode detectors. Lastly, the low frequency noise voltage power spectral density of AC biased diode connected PMOS transistors is comparable to that of commercial GaAs detectors.