Design and test of cryogenic ASICs for the readout of (sub)millimeter bolometers for space applications
In the context of its research program on new (sub) millimeter bolometers for space applications, the CEA’s Institute of Research into the Fundamental Laws of the Universe (IRFU) opens a Postdoctoral position in microelectronic design and cryogenic electronics for two years.
Context
The PACs bolometer arrays aboard the Herschel Space Observatory have showed very good performances since their commissioning in June 2009. These resistive bolometers (2560 multiplexed pixels in total), which were developed by CEA in France, operate at 300 mK and are almost photon noise limited in the range 60 to 210 μm. Based on our developments for the PACS photometer, we are investigating new systems to provide high sensitivity detectors for future sub-millimeter projects. Simulations and preliminary measurements show that PACS like detectors used at very low temperature could be potentially used for future missions. Better performances could be reach with new designs of the detection and electronic pixels on the same wafer (above IC technology). This technology means that the detector and the specific integrated electronics (ASIC) work at the same temperature in the 100 mK range. The CMOS technology used in PACs is no more available. We need to find and to fully characterize a new CMOS technology to build our new integrated electronics.
Description of the main tasks
The project is divided into 3 sections:
- Technology identification
- Design of the ASIC BoRo1 for technology evaluation and technological parameters extraction
- Test of the BoRo1 ASIC at cryogenic temperature (100mK)
1- Technology identification
The first task will be to find the best microelectronic technology for the project.
The potential durability, the functionality at very low temperature and the noise levels will be, when available, the first criteria to take into account for the selection. In addition, the wafer dimension, the quality of the design kit, the availability of the technology via MPW and the cost will be additional conditions to control. The lab has already tested few technologies for space applications (AMS 0.35 µm, AMS 0.18 µm, X-FAB 0.18 µm) for noise parameters extraction.
2- Design of the BoRo1 ASIC
This first cryogenic ASIC will be dedicated to the characterization of the technology selected in the first task. Thanks to the test of this first ASIC, we must be able to measure and extract the main electronic parameters (noise, gm, ileak, VT…) at cryogenic temperature (100 mK). This first ASIC will integrate basic building blocks: stand alone transistors of different sizes and types, capacitors, resistors, switches, ….) but also more sophisticated circuits such as amplifiers and OTAs.
3- Test of the BoRo1 ASIC
The last task will be dedicated to the test of BoRo1. The test involves the design of the boards, the characterization at room and cryogenic temperatures and the drafting of a test report.
Candidate profile
The candidate must have a PhD in microelectronics and/or cryogenic electronics. She/he must already have designed an ASIC and/or electronics for very low temperature applications (less than 4K typically). In addition, a first experience in the design and development of setup boards and test environment would be appreciated. She/he must be very autonomous but also able to easily integrate the microelectronics team and communicate with Physicists and electronics engineer.
Supervisors
Olivier Gevin, DSM IRFU, Service d’Electronique des Détecteurs et d’Informatique (SEDI)
olivier.gevin<στο>cea.fr
Xavier de la Broise, DSM IRFU, Service d’Electronique des Détecteurs et d’Informatique (SEDI)
xavier.de-la-broise<στο>cea.fr
Duration and beginning of the position
1 year renewable.
March 2015.
References
[1] Large high impedance silicon μ-calorimeters for x-rays camera: status and perspectives, Jean-Luc Sauvageot et al., Proceedings Volume 9144: Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray August 2014
[2] Low power, low noise, Charge Sensitive Amplifier in CMOS 0.18 µm technology for the readout of fine pitch pixelated CdTe detector, O. Gevin et al., IEEE Nuclear Science Symposium, 2012
[3] Caliste Microcamera for Hard X-Ray Astronomy, Limousin et al., Semiconductor Radiation Detection Systems, CRC Press, Taylor&Francis group, p193-216, 2010
[4] Imaging X-ray detector front-end with high dynamic range: IDeF-X HD, O. Gevin et al., NIMA, 2011
[5] Vincent Revéret «Etude de Faisabilité d’une Caméra Bolométrique Pour l’Imagerie à Haute Résolution Spatiale à 1,3mm de Longueur d’Onde, pour l’IRAM » Thèse de doctorat Université Paris VI 2004.