Published online by Cambridge University Press: 01 February 2011
We have fabricated and studied an un-cooled micro-bolometer with thermo-sensing layer sandwiched between two electrodes. The micro-bolometer has “bridge” configuration to provide sufficient thermo isolation of the thermo-sensing layer and is made on the surface of silicon wafer by means of surface micro-machining technique. The support layer of SiN and thermo-sensing layer of a-Ge:H,F have been deposited by low frequency PE CVD. The active area of the thermo-sensing layer is Ab=70x66 μm2. Temperature dependence of conductivity σ(T), current-voltage characteristics I(U), spectral noise density and thermal response time have been measured to characterize operation and to determine main performance characteristics. Activation energy of the thermo-sensing layer was Ea=0.34 eV providing thermal coefficient of resistance α=0.043 K-1. Pixel resistance was in the range Rb=(1÷30)x105 Ohm. Current and voltage responsivities were in the range RI=0.3÷14 AW-1 and RU=(1÷2)x105 VW-1, respectively. The value of detectivity was in the range of D*=(1÷40)x108 cmHz1/2W-1 and response time was τ=100 μs. The characteristics obtained in this micro-bolometer with sandwiched thermo-sensing layer make it promising for further development.