Experimental characterization of gold-doped infrared-sensing MOSFET's

Gold in silicon: Characterisation and infra-red detector applications

“…As shown in Figure 5, the gold-doped Mos transistor or MOSFET can be used as a very sensitive detector of infra-red radiation in the 1.0 to 3.0 micrometer wavelength regions (6). The change of gold impurity charge state in the surface depletion region of the MOSFET device structure due to optical emission or photo-ionisation causes a modulation in the conductivity between the drain and source of the transistor.…”

“…The infra-red sensing MOSFET is an integrating detector, and the amount of the decrease in conductivity of the transistor is proportional to the total number of infra-red photons which have been incident on the detector since the beginning of the integration period. Responsivities of 500 Amp/Watt have been observed, or in other words, each incident photon results in a change in the current of 300 electrons and the device has a positive gain as the result of the transistor action (6).…”

“…Again, since the acceptor level is near the centre of the band-gap, both hole and electron emission are important for this level. Conversely, this effect can be used to detect infra-red radiation by observing most conveniently the drain current of a MOSFET under infra-red illumination (6).…”