Research On The Irradiation Effects Of CMOS Image Sensor Under Laser

With the development of large-scale integrated circuit and manufacturing technique, CMOS image sensor is widely used in the national defense, industry and a number of aspects in science and technology, such as surveillance,material science and so on. As a result, the investigations on the irradiation effects of CMOS image sensor are attracting more and more interests. However, previous work on the irradiation effects of CMOS image sensor is focus on the effects caused by high energy particles, while the laser irradiation effects are merely investigated. In this dissertation, the laser irradiation effects on the MT9V022 CMOS image sensor are systematically studied with experiments. The novel irradiation effects of pulsed and CW laser on CMOS image sensor are analyzed. The main results of this dissertation are as follows:1.The experiment phenomenon of the CW and pulsed laser irradiating on CMOS image sensor is studied and discussed. The saturation effects?over saturation effects and crosstalk effects are observed for CW laser successively with the increase of laser power density. Analyzes on the processing circuit of CMOS show that the over saturation effects are mainly caused by the correlated double sampling(CDS) circuits embedded in every pixel of CMOS, while the crosstalk effects are caused by the influences of irradiating laser on the public reference voltage of CMOS. On the other hand, the saturation effects and crosstalk effects are observed for pulsed laser. The behaviors of crosstalk effects are closely related to the irradiating times of the pulses. A notable difference between the CW laser irradiation effects of CMOS and CCD is that for CMOS, the over saturation effects appear at lower laser power densities than that of crosstalk effects, while the results are just opposite for CCD.2. The relationships between the irradiating laser power density and the number saturation pixels are studied. The experiments and theoretical calculations show that the saturation area expands as the laser power densities increases. The saturation pixels away from focus point are mainly caused by the diffraction light through aperture at lower laser power densities, the saturation area is proportional to the 2/3 power of the power densities, while the light scattering from element surfaces play the main role on the saturation effects at higher laser power densities, the saturation area is proportional to the 2/ s power of the power densities.3. The irradiating effects of double-pulsed laser on CMOS are studied. We compare its damage effects with that of the single pulsed laser and find that it is easier for a Double-pulsed laser to cause damages on the CMOS sensor. The underlying mechanics are analyzed.The results of this dissertation have enriched the knowledge of laser irradiation effects. The results may provide valuable advises for the anti-blooming design of opto-electronic devices and be references for the work of laser effectiveness evaluation.