Speaker
Description
Since the 1990s, CEA-LETI has been involved in the development of HgCdTe (MCT) detectors for space and scientific applications, in collaboration with Lynred. For instance, CIRS was a 7-18 µm PC retina manufactured at LETI and sent onboard the Cassini-Huygens probe to study the temperature of Saturn's rings. Subsequently, LETI participated extensively in the development of MTG detectors, with a particular focus on the VLWIR spectral band, which was recently initiated for the purpose of atmosphere chemistry sensing in weather forecasting. In addition, LETI was at the forefront of the development of MCT eAPDs for adaptive optics, with the RAPID detector operating within the SWIR range at a speed of 1.5 kHz. Since 2015, the retina in question has been installed on the PIONER VLTi instrument in Paranal. In recent developments, LETI and Lynred have successfully engineered the ALFA detector, a SWIR 2kx2k focal plane array designed for the detection of low flux. The ALFA array has been dispatched to Mexico for utilisation in the CAGIRE camera, which is specifically designed for the observation and analysis of gamma-ray bursts. In recent times, the emphasis of our developmental efforts has been directed towards the conceptualisation of an entirely novel MCT diode process flow, with the objective of enhancing the performance metrics from SW (2.5 µm CO) to VLWIR (15.5 µm at 80 K). The process flow, here designated NG, has been optimised with the objective of reducing process-induced defects in MCT diodes. The result is a high degree of stability for high flux applications and low persistence in the low flux case. In addition, the capacity to attain a remarkably low dark current in LW (fractions of e/s for 8.5 µm CO at 35 K) with this structure was demonstrated. Concurrent with the imaging activities, eAPDs are being optimised for free space communications or quantum applications, with the objective of achieving photon counting. The lessons learned from these developments are currently being investigated for imaging applications targeting earth observations using the COBRA ROIC from Lynred. In addition to the development of MCT arrays, LETI is collaborating with IIIVLab and Lynred on the research and development of antimony-based T2SL technology for high operating temperature tactical applications in the MW range (5 µm at 130 K). Furthermore, LETI is engaged in the research and development of InGaAs arrays for mass market smartphone applications. In this presentation, we will provide a concise overview of our recent advancements in the field of IR imaging detectors. This will include an exposition of our endeavours in radiation hardness studies of MCT detectors and the analysis of low frequency stability (RTS, LF noise, etc.).