MICROMACHINED ROOM-TEMPERATURE MICROBOLOMETERS FOR MILLIMETER-WAVE DETECTION

We have combined silicon micromachining technology with planar circuit s to fabricate room-temperature niobium microbolometers for millimeter -wave detection. In this type of detector, a thin niobium film, with a dimension much smaller than the wavelength and fabricated on a 1 mu m thick Si3N4 membrane, acts both as a radiation absorber and temperatu re sensor. Incident radiation is coupled into the microbolometer by a 0.37 lambda dipole antenna of center frequency 95 GHz with a 3 dB band width of 15%, which is impedance matched with the Nb film. An electric al noise equivalent power (NEP) of 4.5 X 10(-10) W/root Hz has been ac hieved. This is comparable to the best commercial room-temperature mil limeter-wave detectors. (C) 1996 American Institute of Physics.