Ultra-Small Pixel IR Sensing Array Fabricated with a Post-CMOS Compatible Process

This paper reports an ultra-small pixel (100 µm × 100 µm) infrared (IR) thermopile sensing array with double-level suspended films structure fabricated by a front-side Post-CMOS compatible process. Benefit from the optimized heat dissipation control, the ultra-small thermopile pixel achieves the normalized detectivity of 2.1 × 10
⁷
cm·Hz
^1/2
·W
⁻¹
and the responsivity of 52 V/W in air. Owing to the design of the double-level structure, the device obtains a high fill factor of 0.94. Test results show that the responsivity deviation of each pixel is less than ± 6.6 % and the response time is 1.4 ms. The designed thermopile array indicates a high potential for low-cost and high-resolution IR focal-plane array (IRFPA).