High Operating Temperature Ga-free superlattice photodetector and focal plane array for the full MidWave InfraRed spectral domain (HOT-MWIR).
An Increase of the operating temperature of the high performance cooled infrared (IR) detector focal plane arrays (FPAs) would induce a reduction in size, weight and power consumption of the cryocooler and allow a new class of applications where the needs in portability, compactness and energy autonomy of the IR cameras are essential.
Currently, the photodetector technologies operating at high temperature (T= 150K), in particular the detector based on InAsSb, only cover a part of the midwave infrared (MWIR) domain, below 4.2µm. The extension of the cutoff wavelength to the full MWIR spectrum until 5µm for an operating temperature equal to 150K or higher, with no tradeoffs in performance, would present evident radiometric advantages.
Combining the advantages of superlattice (SL) nanostructures in term of tuning of cut-off wavelength and the ones of XBn barrier structure device, the main objective of the HOT-MWIR project is to fabricate and study the first Ga-free InAs/InAsSb type-II superlattice (T2SL) photodetector FPA. The Ga-free T2SL photodetector on GaSb substrate will be designed in an XBn configuration with a 5 µm cutoff wavelength in order to address the full MWIR domain. Ga-free SL detectors and 320x256 FPAs (TV/4 format), with a 30 µm pixel pitch, will be processed, hybridized and evaluated for temperature operation over 150K.
To reach this challenging objective, the HOT-MWIR project involves five French laboratories with complementary scientific and technological skills : three academic labs (IES, LPA, ILV), one industrial partner (THALES - III-V Lab) and an EPIC (ONERA - public undertaking). These multidisciplinary skills are required to investigate fundamental and applied researches, from the MBE growth of InAs/InAsSb SL structures to the hybridization on read out integrated circuit (ROIC) and to the radiometric characterizations of the FPA, together with detailed studies on optical properties of nanostructures, device physics and chemistry of surfaces and interfaces, using accurate k.p. modeling and magneto-spectroscopy performed on antimonide-based (Sb-based) SL nanostructures, etching and surface passivation of single device and arrays as well as the removing of the GaSb substrate using environmental and safer process ("REACH" conditions).
Considering the many challenges addressed within the project, 48 months are planned to achieve and assess the first MWIR Ga-free T2SL FPA prototype.
Monsieur Philippe CHRISTOL (Institut d'Electronique et des Systèmes)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LPA Laboratoire Pierre Aigrain
ILV Institut Lavoisier de Versailles
ONERA CENTRE PALAISEAU
IES Institut d'Electronique et des Systèmes
Help of the ANR 589,766 euros
Beginning and duration of the scientific project: - 48 Months