A low-cost small pixel uncooled infrared detector for large focal plane arrays using a standard CMOS process

Eminoglu, S
Tanrikulu, MY
Tezcan, DS
Akın, Tayfun
This paper reports the development of a low-cost, small pixel uncooled infrared detector using a standard CMOS process. The detector is based on a suspended and thermally isolated p(+)-active/n-well diode whose forward voltage changes due to an increase in the pixel temperature with absorbed infrared radiation. The detector is obtained with simple post-CMOS etching steps on dies fabricated using a standard n-well CMOS process. The post-CMOS process steps are achieved without needing any deposition or lithography, therefore, the cost of the detector is almost equal to the cost of the fabricated CMOS chip. Before suspending the pixel using electrochemical etch-stop technique in TMAH, the required etch openings to reach the silicon substrate are created with a simple dry etch process while CMOS metal layers are used as protection mask. Since the etch mask is implemented with available CMOS layers, the etch openings can be reduced significantly, allowing to implement small pixel sizes with reasonable fill factor. This approach is used to implement a 40mumx40mum diode pixel with a fill factor of 44%, suitable for large format FPAs. The p(+)-active/n-well diode has a low 1/f noise, due to its single crystal nature and low bias requirement. Optimum pixel performance is achieved when the pixel is biased at 20muA, where self-heating effect is less than 0.5K. Measurements and calculations show that this new detector has a thermal conductance (G(th)) of 1.4x10(-7)W/K and provides a responsivity (R) of 5800V/W and a detectivity (D) value of 1.9x10(9)cm Hz/W when scanned at 30fps with an electrical bandwidth of 4kHz. If this detector is used to implement a 64x64 or 128x128 FPA with sufficient number of parallel readout channels, these FPAs will provide an NETD value of 195mK considering only the detector noise. When the readout noise is included, these FPAs are expected to provide NETD value below 300mK. Such FPAs are very suitable for ultra low-cost infrared imaging applications.
Conference on Infrared Detectors and Focal Plane Arrays VII


A low-cost 128x128 uncooled infrared detector array in CMOS process
Eminoglu, Selim; Tanrikulu, Mahmud Yusuf; Akın, Tayfun (2008-02-01)
This paper discusses the implementation of a low-cost 128 x 128 uncooled infrared microbolometer detector array together with its integrated readout circuit (ROC) using a standard 0.35 mu m n-well CMOS and post-CMOS MEMS processes. The detector array can be created with simple bulk-micromachining processes after the CMOS fabrication, without the need for any complicated lithography or deposition steps. The array detectors are based on suspended p(+)-active/n-well diode microbolometers with a pixel size of 4...
The First Fabricated Dual-Band Uncooled Infrared Microbolometer Detector with a Tunable Micro-Mirror Structure
Keskin, Selcuk; Akın, Tayfun (2012-04-27)
This paper presents the first fabricated dual-band uncooled resistive infrared thermal microbolometer implemented with a resistive microbolometer and a tunable micro-mirror structure. Tunable reflective micro-mirrors are suspended underneath the suspended resistive microbolometers having a 35 mu m pixel pitch, and they are switched between two positions by the application of an electrostatic force for obtaining different responses in two wavelength infrared atmospheric windows, namely the 3-5 and 8-14 mu m,...
An uncooled microbolometer infrared focal plane array in standard CMOS
Tezcan, Ds; Eminoglu, S; Akar, Os; Akın, Tayfun (2001-01-24)
This paper reports implementation of a low-cost microbolometer focal plane array using n-well layer in a CMOS process as the microbolometer material. N-well microbolometer structures are suspended for thermal isolation by postetching of fabricated CMOS dies using silicon bulk-micromachining techniques. Although n-well has a moderate TCR of 0.5-0.65 %/K at 300 K, it still provides a reasonable performance due to its single crystal structure which contributes low 1/f noise. Detailed thermal simulations in ANS...
Low-cost uncooled infrared detector arrays in standard CMOS
Eminoglu, S; Tanrikulu, MY; Akın, Tayfun (2003-04-25)
This paper reports the development of a low-cost 128 x 128 uncooled infrared focal plane array (FPA) based on suspended and thermally isolated CMOS p(+)-active/n-well diodes. The FPA is fabricated using a standard 0.35 mum CMOS process followed by simple post-CMOS bulk micromachining that does not require any critical lithography or complicated deposition steps; and therefore, the cost of the uncooled FPA is almost equal to the cost of the CMOS chip. The post-CMOS fabrication steps include an RIE etching to...
High performance HgCdTe photodetector desings via dark current suppression
Özer, Yiğit; Kocaman, Serdar; Department of Electrical and Electronics Engineering (2018)
This thesis work covers the numerical analysis and design of infrared photon detectors with a focus of HgCdTe based devices. An in-house numerical tool is utilized for the design and characterization process, where the Poisson, current and continuity equations are solved numerically with the high precision in electrical and optical properties. A high operating temperature alternative substrate mid-wave HgCdTe detector is designed benefiting from the generation-recombination dark current suppression. The adv...
Citation Formats
S. Eminoglu, M. Tanrikulu, D. Tezcan, and T. Akın, “A low-cost small pixel uncooled infrared detector for large focal plane arrays using a standard CMOS process,” Orlando, FL, 2002, vol. 4721, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39743.