Broadband terahertz imaging with highly sensitive silicon CMOS detectors

CEA-LETI, MINATEC Campus, 38054 Grenoble, France.
Optics Express (Impact Factor: 3.49). 04/2011; 19(8):7827-32. DOI: 10.1364/OE.19.007827
Source: PubMed

ABSTRACT This paper investigates terahertz detectors fabricated in a low-cost 130 nm silicon CMOS technology. We show that the detectors consisting of a nMOS field effect transistor as rectifying element and an integrated bow-tie coupling antenna achieve a record responsivity above 5 kV/W and a noise equivalent power below 10 pW/Hz(0.5) in the important atmospheric window around 300 GHz and at room temperature. We demonstrate furthermore that the same detectors are efficient for imaging in a very wide frequency range from ~0.27 THz up to 1.05 THz. These results pave the way towards high sensitivity focal plane arrays in silicon for terahertz imaging.

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Available from: Laurent Dussopt, Sep 02, 2015
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    • "mW = 842 V/W at Z a = 50 (325 times) than those of sample B (75 times) from the result of the detector without antenna as shown in inset from Ref. [7], even if sample B and C have same criterion of Z gs < 50 as expected in Fig. 3. The lowest noiseequivalent-power (NEP) in sample C (inset) has been obtained as 18 pW/ √ Hz at V GS -V T = 0.25 V commonly based on the channel thermal noise (N = (4kTR ch ) 0.5 ), which is comparable with the reported lowest NEP values for antenna-coupled plasmonic Si-based THz detectors [3], [19], owing to the relatively low channel resistance (R ch ) from large micron-scale width for low-impedance MOSFET design. It can be noted that these enhancement trends of R v and NEP in sample C with thinner T ox mainly originate from increase of the plasmonic channel electron density modulation by T ox scaling. "
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    ABSTRACT: We demonstrate the performance enhancement of field-effect transistor (FET)-based plasmonic terahertz (THz) detector with monolithic integrated antenna in low-impedance regime and report the experimental results of Si MOSFET impedance in THz regime using 0.2-THz measurement system. By designing FET with low-impedance ranges (<1 k) and integrating antennas with impedances of 50 and 100 , we found that our low-impedance MOSFETs have the input impedance criterion of 50 at 0.2 THz and the MOSFETs with thinner gate oxide show the highly enhanced plasmonic photoresponses at 50-antenna by 325 times from the result of the detector without antenna.
    IEEE Electron Device Letters 03/2015; 36(3):220-222. DOI:10.1109/LED.2015.2394446 · 2.75 Impact Factor
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    • "Terahertz plasmonic field effect transistor (FET) detectors [1] implemented in Si [2] [3] [4] [5], GaAs/InGaAs [6] [7] [8], GaN, [9] and graphene technologies [10] demonstrated responsivities up to 5.8 kV/ W [11] and up to 90 kV/W with on-chip amplifiers [12] [13] [14]. These devices could be also used as mixers [15], THz mirrors [16], and THz sources [17] [18]. "
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    ABSTRACT: The terahertz SPICE FET model has been experimentally validated in Si CMOS and InGaAs HEMTs up to 4.5 THz and updated to account for parasitic gate fringing capacitance and parasitic source and drain resistance. The model is in good agreement with experimental data at low and high THz field intensities. We also show that introducing additional capacitances linking the drain and gate electrodes may lead to enhancement of the THz plasmonic detector response at lower THz frequencies. The simulation results of the plasmonic detector response to a single terahertz pulse are in good agreement with our measured data.
    Solid-State Electronics 02/2015; 104. DOI:10.1016/j.sse.2014.10.013 · 1.50 Impact Factor
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    • "THz detectors based on field-effect transistors (FET) [1] show high responsivity (up to a few kV/W), low noise equivalent power (down to 10 pW/Hz 1/2 ) [2] and fast response time (below 1 ns) [3] [4]. The combination of fast response and high sensitivity makes THz FETs promising as detectors for monitoring many THz sources. "
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    ABSTRACT: Terahertz power dependence of the photoresponse of field effect transistors, operating at frequencies from 0.1 to 3 THz for incident radiation power density up to 100 kW/cm2 was studied InGaAs high electron mobility transistors. The observed signal saturation behavior is explained by analogy with current saturation in standard direct currents output characteristics. The theoretical model of terahertz field effect transistor photoresponse was developed shows a good description match with experimental data. Our experimental results show that dynamic range of field effect transistors based terahertz detectors is very high and can extend from mW/cm2 up to kW/cm2.
    2014 26th International Conference on Indium Phosphide and Related Materials (IPRM); 05/2014
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