Experiment on the temporal evolution characteristics of a CCD multilayer structure irradiated by a 106  μm continuous laser

Abstract

In this study, an experiment of a CCD detector irradiated by a 1.06 μm continuous laser is established. Factors including the microlens focusing beam, microlens carbonization at high temperature, shading aluminum film opening rate, low shading aluminum film absorption rate, and different materials' absorption to the laser are comprehensively considered. By combining the irradiation time, the output image of the CCD detector, surface morphology of the damage area, the optical micrograph, and regional energy spectrogram, the damage mechanism of the CCD is explored. In addition, the threshold time and the damage morphology of the multilayer structure of the CCD detector are investigated. The results show that when the irradiation time increases, the damage starts from the microlens due to melting, which is represented as point damage. Subsequently, the aluminum film melts and is separated from the SiO by stress and melting damage, causing vertical bright linear damage. Without the protection of the shading aluminum film, the silicon electrode heats up and reaches the melting point, causing damage to the wiring circuit, which is represented as horizontal dark linear damage. Eventually, the N-Si layer in the silicon substrate melts and the clock signal is destroyed, which means that the optical signal is not converted into an electrical signal. The CCD detector gets completely damaged.

Laser-induced damages to charge coupled devices with combined nanosecond/picosecond short-pulse lasers

“…Specifically, the heat absorbed by the photosensitive region is diffused in the form of heat conduction. Due to the difference of thermal conductivity, the materials inside CCD demonstrate distinctive temperature field distribution and thermal expansion, which generates different thermal stress distribution [17].…”