The thermal deflection theoretical model of a pizeoresistive composite micro-cantilever for thermal Infrared detector is studied. A novel tri-layer Si-based micro-cantilever thermal infrared detector with carbon nanometer tube film is fabricated using standard integrated circuit and micro-mechanical process technology. It is based on the characteristics that the composite micro-cantilever bend in response to incident IR thermal radiation due to the bi-material effect by different thermal expansion coefficient of Al and Si. The bending of micro-cantilever is piezoresistively detected. Furthermore

a new infrared absorbing layer material—carbon nanotubes (CNTs) is coated in order to enhance infrared radiation absorbing characteristic. The input-output characteristic of the piezoresistive micro-cantilever IR thermal detector with carbon nanometer tube film is studied by experiment. The experimental result shows that carbon nanotubes as the absorbing layer of a micro-mechanical cantilever could achieve higher sensitivity. The power resolution is increased twice.