HgCdTe Avalanche Photo Diodes (APDs) are developed at CEA/Leti to enable applications that require the detection of information contained in a low number of photons in each spatial and/or temporal bin, such as LiDAR and free space optical communications. The requirements for such detectors are strongly application dependent, which is why both the HgCdTe APD technology and the proximity electronics, used to extract the detected photocurrent, needs to be optimized for each application. The present communication reports results obtained from the development of detectors for high dynamic range LiDAR applications, made within the scope of the H2020 project HOLDON, and high data rate FSO, made in collaboration with Mynaric Lasercom AG. For FSO applications, we have measured 10 GHz bandwidth at unity gain for APDs with 10 μm diameter. At higher APD gain and diameter, the BW is presently limited by carrier transit and by resistance-capacitance product in small and large area APDs, respectively. For LiDAR we have developed APDs with an made of an array of diodes in parallel with a diameter up to 200 μm and large avalanche gain, M<100, that will be hybridized with a dedicated CMOS amplifier. This circuit was designed to enable photon shot noise limited linear detection over a dynamic range of 6 order of magnitude of signal for observation times ranging from ns up to μs. First characterizations made at unity APD gain shows that the HOLDON detector will meet most of the required performance parameters in terms of sensitivity and linear dynamic range.
This LETI/Sofradir/Defir study aims at realizing sub-10 μm pitch HgCdTe infrared FPAs. To cope with the different diode process issues related to pitch reduction-morphologic realization, short-circuits, FTM optimization - a parametric study was carried out - contact size, passivation properties, doping levels, diode processing conditions-. A wafer-level test campaign was conducted to evaluate the process window. It revealed functional MWIR diodes from 15 μm to 3 μm pitch. 7.5 μm pitch 640×512 and 5 μm pitch 64×152 FPA were characterized and turned out to be functional.
Multicolor detection capabilities, which bring information on the thermal and chemical composition of the scene, are desirable for advanced infrared (IR) imaging systems. This communication reviews intra and multiband solutions developed at CEA-Leti, from dual-band molecular beam epitaxy grown Mercury Cadmium Telluride (MCT) photodiodes to plasmon-enhanced multicolor IR detectors and backside pixelated filters. Spectral responses, quantum efficiency and detector noise performances, pros and cons regarding global system are discussed in regards to technology maturity, pixel pitch reduction, and affordability. From MWIR-LWIR large band to intra MWIR or LWIR bands peaked detection, results underline the full possibility developed at CEA-Leti.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.