Abstract:The pixel-level digital infrared detector has higher performance and anti-interference ability, which is one of the important directions of infrared detector technology development. By breaking through key technologies such as pixel-level digital readout circuit design, low peak-valley HgCdTe material epitaxy, device fabrication process, and flip-chip connection, a 512×8 pixel-level digital long-wave infrared detector assembly is developed, and its performance is tested. The results show that this detector assembly can meet the system requirements, with spectral response range of 7.85-10.17 μm, average peak responsivity of 1.4×10¹¹ LSB/W, responsivity non-uniformity of 9.13%, operable pixel factor of 97.5%, noise equivalent temperature difference (NETD) of 4.4 mK and dynamic range of 90.6 dB.

Abstract:As one of the characteristics of detector components, the responsivity non-uniformity has an important impact on its practical applications, especially in the low-background space application. The uneven contact-hole size of large-format detector chip is one of the factors which lead to the non-uniformity of device responsivity. The contact-hole etching process of the large-format long-wave infrared detector chip with 1280×1024 pixels is studied, and the optimization measures are proposed. The result shows that the proposed method can improve the uniformity of the etching process, thus improving the responsivity non-uniformity of detector components.

Abstract:In order to analyze the problem of the increase of blind elements in the long-wave HgCdTe detector under high and low temperature environments, the long-wave HgCdTe detector assembly is tested through experiments and the output images are observed. It can be found that the corrected detector image changes after changing the ambient temperature. Analyze the cause and verify it experimentally. The results show that the ambient temperature can affect the output image and performance of the detector, that is, changes in the operating temperature of the chip can cause changes in dark current and wavelength.

Abstract:With the rapid development and increasingly expanding application fields of RF/microwave devices, various device integration processes based on semiconductor monolithic integration technology have been developing. A GaAs compound substrate with AlGaAs-InGaAs is studied. The succinic acid wet etching process has less influence on the electrical performance of the device. The depleted and enhanced pseudomorphic high-electron-mobility transistor (pHEMT) devices are integrated into the same chip semiconductor process technology. The results show that the Y-gate of enhanced transistor has a linewidth of 0.25 m and an opening voltage of 0.3 V; the gate of depleted transistor has a linewidth of 0.5 m and an opening voltage of -0.8 V. The gate voltage distribution from negative to positive on the same chip is realized, and a broader design platform for designers is provided. This integration technology can be applied to fields such as low noise amplifiers, linear antenna switches, filters, and power control devices.

Abstract:In order to verify the influence of beam intensity distribution on film thickness, the distribution of epitaxial film was simulated by theoretical calculation of beam current distribution, and the data were compared with the samples of epitaxial experiment. The results confirmed our guess, which can partially explain the uneven distribution of film thickness. Using the formula to calculate the distribution of beam intensity, the thinnest point should be 73.26% of the thickest point. While the thickest point of the experimentally tested film thickness was 8.1582 μm, the thinnest point was 5.9362 μm, the ratio was 72.76%, which was basically consistent with the calculation results. Therefore, it can be determined that the beam intensity distribution has a certain influence on the film thickness. However, the film thickness of the actual material is not only affected by the beam distribution, but also related to other process parameters. Due to the comparison between theoretical calculations and experiments, the results obtained are more accurate and reliable than those obtained by simple experiments.

Abstract:Using the L-band sounding data from Shanghai Baoshan Station, the inversion of temperature data of GIIRS/FY-4A Geostationary Interferometric Infrared Sounder (GIIRS) with different quality control data was analyzed under clear sky, cloudy sky and all sky in typhoon season within 24 hours before and after typhoon landing. The results show that: (1) The inversion accuracy of GIIRS temperature is best under clear sky, and the data root mean squared error (RMSE) with quality control of 0 is 1.74 K, which indicates that the inversion product in the upper troposphere has a certain degree of credibility. (2) The cloud layer reduces the accuracy of GIIRS temperature inversion. The data RMSE with quality control of 0 is 3.57 K under cloudy sky, which exceeds the standard error range given by the US Environmental Monitoring System. (3) When the temperature is greater than 230 K under cloudy sky, the inversion temperature of GIIRS is lower than the sounding data detection temperature. (4) Within 24 hours before the landing of typhoon “Ampil” and “Jongdari”, at the tropopause layer and from the height of 500 hPa to the planetary boundary layer, GIIRS inversion temperature is higher; within 24 hours after the landing of typhoon “Jongdari”, from the height of 800 hPa to the phanetary boundary layer,the inversion temperature of GIIRS is lower. The inversion will generate a large number of invalid values.

Abstract:Taking the typhoon "Choi-wan" on the 14th of 2009 as an example, based on CloudSat related cloud products, the effective particle radius and cloud water content distribution characteristics of water and ice clouds in the deep convection cloud of the typhoon were calculated. On this basis, the correlation between the two cloud microphysical parameters was discussed, and the application test of this relationship was performed for multiple typhoons in different development periods. The results show that, for both water clouds and ice clouds, if the water content of clouds is taken as the x-coordinate and the effective particle radius of clouds as the y-coordinate, the distribution of scatter map of the typhoon deep convective cloud pixel has an obvious lower boundary. The boundary value gradually increases with the increase of effective particle radius and cloud water content parameters. The effective particle radius of low-level water clouds below the zero layer has a positive correlation with the liquid water content, which can be fitted using a logarithmic relationship. The test shows that the fitting relationship is also applicable to typhoons in other stages of development, confirming the universality of the relationship.