The short-wavelength infrared (SWIR) InGaAs focal plane array (FPA) detector consists of infrared detector chip, readout integrated circuit (ROIC), and flip-chip bonding interconnection by Indium bump. In order to satisfy space application requirements for failure rates or Mean Time to Failure (MTTF), which can only be demonstrated with the large number of detectors manufactured, the single pixel in InGaAs FPAs was chosen as the research object in this paper. The constant-stress accelerated life tests were carried out at 70°C，80°C，90°C and100°C. The failed pixels increased gradually during more than 14000 hours at each elevated temperatures. From the random failure data the activation energy was estimated to be 0.46eV, and the average lifetime of a single pixel in InGaAs FPAs was estimated to be longer than 1E+7h at the practical operating temperature (5°C).
Space infrared detector is the core component of photoelectric conversion in the infrared system, the indicator of which, such as sensibility and reliability, limits the optimum performance of the detection system. In the reliability research of infrared detector, the operating life of the device is a very important index and also a significant subject in the engineering application. In the accelerated life test of space infrared detector, it was difficult to periodically measure blackbody response signal of infrared detector, due to equipment limitations for a long time. Accordingly, it was also hard to get abundant failure data of devices for statistical analysis. For this problem, we designed a novel multi-station testing system for accelerated life test of space infrared device, in which response signal as well as temperature can be measured in-situ and recorded for further analysis. Based on theoretical calculation and analysis of actual measured data, we studied and designed the mechanical structure of the equipment and the key component of the testing system, such as the displacement platform, illustrated the control algorithm and put up a system design proposal which meet the testing requirements well. This work technically supports the accelerated life test of space infrared device.
In this paper, an automatic measuring system based on LABVIEW and PLC is introduced; it uses the mutual controls of Single-Chip computer (MCU) and LABVIEW to accomplish the electrical parameter measurements of infrared detectors. This system can realize the multiple parameter measurements of no less than 160 IR detectors, it can realize the collection and storage of results by the LABVIEW; and it can avoid the damage of the IR detector during the measurement. After thousands times of test, the results show that the system runs stably and it can meet the accurate parameter measurement of detector.
Generally the electrical interconnectivity between The Mercury Cadmium Telluride (MCT) infrared focal plane array
(IRFPA) device and circuit takes the flip chip technology using indium bump as a connection medium. In order to improve
the reliability of the interconnectivity indium melting is a common packaging technique at present. This technique is called
reflow soldering. The heating is transferred to the indium bump by heating the device and circuit. This heating process will
persist about 10 minutes resulting in the MCT material going through a 10 minutes high temperature baking course. This
baking process will strongly degenerate the characteristic of the MCT device. Under this circumstance this article gives a
new heating technique for indium bump which is call induction heating melting technique. This method realizes the
selective heating. While the indium bump is melted by the conduction heating the semiconductor material such as MCT
can’t be heated.
Thermal stress is a common problem as for the cryogenic IRFPA (Infrared Focal Plane Array) Assembly, especially
when the assembly is in large scale. The stress is generated when the assembly enduring times of temperature cycling
ranging from 80K to 300K approximately. This huge temperature change and the mismatch of the CTE (coefficient of
thermal expansion) between these materials by which the assembly is made results in severe thermal stress in the IRFPA.
This thermal stress is the main reason for the failure of assembly during temperature cycling such as the degradation of
device performance and even the die crack. To improve the reliability of the FPA assembly reducing the thermal stress
becomes a more important issue. This article presents several results of the analysis of the thermal stress of IRFPA
assembly using FEM (Finite Element Method). According to this result we have got an optimal design of the assembly
This paper presents the recent progress on the study of device processings at multilayer HgCdTe film for integrated two-color (SWIR/MWIR) n-p-P-P-N detector arrays. The four-layer p-P-P-N heterostructures Hg1-xCdxTe film needed to achieve two color detector arrays was grown by molecular beam epitaxy (MBE) on (211)B oriented GaAs substrates. The secondary ion mass spectroscopy (SIMS) data for the HgCdTe film was obtained. The p-type layer on top of a thin P-type potential barrier layer and the SWIR P-on-N homojunction photodiode formed in-situ during MBE growth using indium impurity doping was processed into the MWIR planar photodiode by selective B+-implantation. The preliminary 256×1 linear arrays of SWIR/MWIR HgCdTe two-color FPAs detector were then achieved by mesa isolation, side-wall passivation and contact metallization. At 78K, the average R0A values of SWIR and MWIR are 3.852×105 Wcm2 and 3.015×102 Wcm2, and the average peak detectivities Dλp* are 1.57×1011cmHz1/2/W and 5.63×1010 cmHz1/2/W respectively. The SWIR photodiode cut-off wavelength is 3.04μm and the MWIR photodiode cut-off wavelength is 5.74μm, quite consistent with the initial device design. The SWIR response spectrum of the two-color detector with a distinct fall-off at shorter wavelength regime was discussed especially.