A 256×256 Focal Plane Arrays Based on InAs/GaAs Quantum Dot Infrared Photodetector

Quantum dot infrared photodetector is extension of quantum well infrared photodetector and is expected to possess the physical potential to achieve the highest IR detector performance. This paper reports a backside-illuminated 256×256 infrared focal plane array based on InAs/GaAs quantum dot device with special designed AlGaAs blocking layers. The quantum dot structures were grown by solid-source molecular beam epitaxy and showed broadband normal-incidence photo response. The response peaks are tunable depending on device structure and applied bias voltage. High performance silicon CMOS read out integrated circuit was developed following standard foundry compatible processing. Indium bump and lip chip bonding technology were utilized to electrical and mechanical hybridization between the FPA detectors and read out chip. A specific detcivity of above 1×1010 cm-Hz1/2/W was achieved at 80 K and a bias of 0.3 V. The thermal image of 256×256 QD FPA has been demonstrated at temperature as high as 135 K.