Surface micromachined cantilever arrays for infrared imaging

This paper presents the design, fabrication and performance of a bimaterial microcantilever focal plane array (FPA) of 256×256 pixels for uncooled infrared (IR) imaging. The microcantilevers made of silicon nitride (SiNx) and gold (Au) convert incident IR energy to a distribution of deflection angles among the FPA pixels according to the IR source, which is read out by an optical method. The thermo-mechanical sensitivity of the cantilever pixel was measured to be 147 nm/K. The noise equivalent temperature difference (NETD) of the FPA was theoretically estimated to be 130 mK and the response time was calculated to be 12 ms. Thermal image of the heated brand iron were captured by the fabricated FPA. The most valuable feature of the implemented FPA is their scalability to high resolution formats without progressively growing fabrication complexity and cost.