It is of great significance to research the laser irradiation effect and failure mechanism of the detector to optimize its performance. In this paper, the 512×1 linear array HgCdTe detector was used as the research object to study its damage phenomenon and mechanism. We used a picosecond pulsed laser with a wavelength of 1064 nm to irradiate the line array HgCdTe detector and found that some pixels of the detector were damaged when the laser energy density was greater than 700 mJ/cm2, and the damaged pixels showed different degrees of response without light conditions, but other undamaged pixels could respond normally. In one experiment, the detector was completely unable to respond normally when the laser energy was too large. To research the mechanism of laser-induced detector damage, we detected the damaged detector chip by using scanning electron microscopy and established a three-dimensional simulation model using COMSOL Multiphysics simulation software. Research showed that the temperature of the chip was too high and mercury was precipitated under high-energy laser irradiation, then the material composition changed and the resistance of the PN junction depletion layer changed accordingly, resulting in the damaged pixels showing different degrees of response without light conditions, but undamaged pixels could respond normally. When the readout circuit pin was damaged by a high-energy laser, the detector was completely unable to respond normally.
It is of great significance to research the laser irradiation effect and failure mechanism of the detector to optimize its performance. In this paper, the 512×1 linear array HgCdTe detector was used as the research object to study its damage phenomenon and mechanism. We used a picosecond pulsed laser with a wavelength of 1064 nm to irradiate the line array HgCdTe detector and found that some pixels of the detector were damaged when the laser energy density was greater than 700 mJ/cm2, and the damaged pixels showed different degrees of response without light conditions, but other undamaged pixels could respond normally. In one experiment, the detector was completely unable to respond normally when the laser energy was too large. To research the mechanism of laser-induced detector damage, we detected the damaged detector chip by using scanning electron microscopy and established a three-dimensional simulation model using COMSOL Multiphysics simulation software. Research showed that the temperature of the chip was too high and mercury was precipitated under high-energy laser irradiation, then the material composition changed and the resistance of the PN junction depletion layer changed accordingly, resulting in the damaged pixels showing different degrees of response without light conditions, but undamaged pixels could respond normally. When the readout circuit pin was damaged by a high-energy laser, the detector was completely unable to respond normally.
KEYWORDS: Mercury cadmium telluride, Pulsed laser operation, Laser irradiation, Semiconductors, Signal detection, Temperature metrology, Photovoltaics, High power lasers, Electric field sensors
To study the effects of the semiconductor structure of the HgCdTe detector by high-energy pulsed light irradiation, building 2D models to simulate the changes of the internal temperature and the structure of the PN junction of the HgCdTe chip after being irradiated by a high-energy pulsed light with wavelength of 1064 nm. Simulation results show that after being irradiated by a high-energy pulsed light, the PN junction of the detector chip will disappear briefly, at the same time, a high temperature is generated on the illumination surface of the chip, and a temperature difference is formed inside the chip. After the laser irradiation, the temperature difference inside the chip changes the distribution of the carriers, creating a temperature difference electromotive force, offsets some of the built-in electric field in the PN junctions, deviating the HgCdTe detector from its normal operating state.
A new phenomenon was discovered in the experiment of the HgCdTe detector irradiated by the laser, namely the photoinduced latch-up effect. Based on this phenomenon, a two-dimensional simulation model of laser irradiation on the detector chip was established by using COMSOL Multiphysics simulation software. The carrier concentration distribution, photo-induced current, and temperature in the photosensitive chip were simulated after being irradiated by a single-pulse laser with different power to explore the principle of the latch-up effect triggered by the laser. The research shows that there is a PNPN structure in the photosensitive chip, with parasitic bipolar transistors PNP and NPN. Both parasitic transistors are turned off if the photosensitive chip is working normally. A large number of photo-generated carriers are generated when the photosensitive chip is irradiated by a high-power pulse laser, and the two parasitic transistors are triggered to conduct and form a positive feedback loop, resulting in a large current and triggering the latch-up.
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