Sensors and Actuators A 199 (2013) 297–303 Contents lists available at SciVerse ScienceDirect Sensors and Actuators A: Physical jo ur nal homepage: www.elsevier.com/locate/sna Monolithic integration of uncooled PbSe bicolor detectors M.C. Torquemada ∗ , V. Villamayor, L.J. Gómez, G. Vergara 3 , M.T. Rodrigo, G. Pérez 4 , I. Génova 1 , I. Catalán 1 , D. Fernández, R.M. Almazán, M. Álvarez 1 , C. Sierra 1 , C.M. Gutiérrez 1 , M.T. Magaz 2 , J. Plaza Instituto Tecnológico la Mara˜ nosa (ITM), Área de Optrónica y Acústica, Unidad de Fotónica, Arturo Soria 289, 28033 Madrid, Spain a r t i c l e i n f o Article history: Received 19 March 2013 Received in revised form 4 June 2013 Accepted 14 June 2013 Available online xxx Keywords: Uncooled IR detector PbSe Spectral discrimination Gas detection Interference filter Monolithic integration a b s t r a c t We report on the manufacture of a dual band uncooled infrared detector of lead selenide for smart detection of IR emitters. The first advanced bicolor PbSe sensor with its spectral response modified by design for our purpose has been developed by means of the monolithical integration of two high- pass interference filters and polycrystalline PbSe sensors. Wavelength cut-on of the filters was 3.7 and 4.3 m. Room temperature detectivities of unfiltered lead selenide yield values of D*pk (3.6 m, 330 Hz, 1 Hz) ∼ 10 9 cm Hz 1/2 /W. Considering the excellent properties of this MWIR sensor, the possibility of enhancing it with a selected spectral response opens its use to a wide range of applications. © 2013 Elsevier B.V. All rights reserved. 1. Introduction New generation of sensors integrate advanced optics, sensitive materials, electronics and algorithms. High sensitivity and selectiv- ity, fast response and low false alarm rates are key technical factors for detection. Integrated spectral discrimination is therefore one of the most demanded features to be added to new detector capa- bilities. Two approaches can be carried out to obtain integrated multispectral detectors. One method is the hybrid integration [1,2], in which detector and filter are bonded together once these com- ponents are independently made up. Disadvantages are the low precision and low optical efficiency of the final device. The other one is the monolithic integration method, in which filter is directly manufactured on the corresponding pixels of the detector die [3]. Though this method is more complex for processing, it provides devices of higher precision, higher optical efficiency and more com- pactness. ∗ Corresponding author. Tel.: +34 913954538; fax: +34 913954613. E-mail address: mtorvic@oc.mde.es (M.C. Torquemada). 1 ISDEFE (Ingeniería de Sistemas para la Defensa de Espa ˜ na) staff providing tech- nical assistance for ITM. 2 NTGS (New Technologies Global Systems) staff providing technical assistance for ITM. 3 Present address: NIT (New Infrared Technologies) S.L. Vidrieros 30, Nave 2 (Prado del Espino), Boadilla del Monte, 28660 Madrid, Spain. 4 Present address: Instituto de Ciencias de la Construcción Eduardo Torroja (IETcc–CSIC), Serrano Galvache 4, 28033 Madrid, Spain. During the last twenty years, important efforts have been made to develop technologies related to uncooled IR detectors. As a result, many thermal detectors are now available in the market. Their advantages are low price and wide spectral response, but present fundamental limitations regarding long response times. Some applications, like the one described in this paper, demand faster uncooled detectors. The solutions have to be searched in the field of photonic detectors. PbSe detectors are photoconductors with optimum response in the MWIR region; they are photonic, so they have fast response and high detectivity at room tempera- ture, are rugged to endure environmental conditions and provide low cost detecting devices [4,5]. Considering the excellent prop- erties of this MWIR sensor, the possibility of enhancing it with a selected spectral response opens its use to a wide range of appli- cations, such as smart detection of IR emitters or gas detection, where simultaneous detection in several infrared bands is a great advantage. This paper reports on the detectors developed for “MUNIN” (INtelligent subMUNition development) project. This project con- sisted in the development of a technological demonstrator provided with IR detection and intended for detection of targets emitting infrared radiation, like non-guided smart submunition. One of the fundamental requirements of the system due to its operation during flight is that the detector must have a response time not greater than a hundred of microseconds. For this pur- pose, it was decided to develop a PbSe sensor for working in the 3 to 5 microns range, in order to have fast response and an opti- mal discrimination by means of thermal contrast between targets 0924-4247/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.sna.2013.06.015