Small two-dimensional and linear arrays of polycrystalline SiGe microbolometers at IMEC-XenICs

The state-of-the-art characteristics of polycrystalline SiGe microbolometer arrays are reported. An NETD of 100 mK at a time constant of 25 ms is achievable on 14×14 and 200×1 arrays at the system level. It is the result of joint studies targeted at 1/f noise decrease, as well as TCR and uniformity improvements together with the design optimization. Thanks to successful decrease of 1/f noise of SiGe, the arrays were moved from "1/f-noise limited" to "system limited", i.e. to the case of VO_x arrays. The mechanical design of pixels was improved affording very precise tuning of the infrared quarter-wave resonant cavity. The resistance and TCR non-uniformity with σ/μ better than 0.2% combined with about 1% noise nonuniformity and 100% pixel operability are demonstrated. The first lots of arrays with 99.98% production pixel yield have already been characterized and the results are being reported.