Characteristics of the indium-doped infrared sensing MOSFET(IRFET)

The operation and characteristics of the indium-doped infrared sensing MOSFET(IRFET) in the 2.0- to 7.0-µm wavelength range are described. Responsivities of 4.8 mA/µJ are easily achieved using relatively large devices with small W/L ratios. Determination of the thermal emission rate of the indium center in silicon indicates that operating temperatures of lower than 50 K are required. Application considerations in large-scale integrated infrared imaging arrays are discussed. The measurement of the thermal emission rate and photoionization cross section of indium also demonstrates the capability of the MOSFET device structure in characterizing shallower level impurity centers in silicon.