Optimization Of Silicon-based Blocked Impurity Band Infrared Detectors And Cryogenic Readout Circuits Exploration

Deep space exploration and infrared astronomical technology need high-performance long-wave infrared detectors,but China is relatively backward in this respect.With the advantages of wide response band,high response rate,fast response speed,easy to prepare in large scale and easy to be read out,the detector of blocked impurity band?BIB?has become the first choice of infrared detectors in the past 30 years.The silicon-based BIB detector is compatible with CMOS technology,easy to be prepared on a large scale and easy to interconnect with readout circuits.At present,the silicon-based BIB detector is still in its infancy in China and has much room for development and improvement.In this dissertation,the optimization of the performance of silicon-based BIB detector and its cryogenic readout circuits are studied and explored.Through experiment and theoretical analysis,the manufacturing process and physical model of the silicon-based BIB detector are optimized;the optical absorption layer of the silicon-based epitaxial BIB detector is designed and optimized from simulation and experiment to enhance the optical absorption;the basic structure units of the cryogenic readout circuits are designed and tested.The innovative research results are as follows:1.Ion-implanted Si:P and Si:As BIB detectors have been fabricated by using integrated circuits compatible process.Both detectors reach the detectivity of 10¹³cm?hz^1/2/W.At 5 K temperature and a dc bias voltage of-2.3 V,Si:P BIB detector shows peak response at 27.3?m,detector response band width of 2.5?40?m,and dark current of 1.12×10^-11A.The blackbody responsivity of the device is 4.59 A/W?800 K blackbody,277 Hz?,corresponding to a detectivity of 4.89×10¹³cm?Hz^1/2/W.Si:As BIB detector presents peak response at 23.8?m.The blackbody responsivity of Si:As device is 3.65 A/W?800K blackbody,277Hz?at 5 K,corresponding to a detectivity of 5.22×10¹³cm?Hz^1/2/W.The detector fabricating process is compatible with that of integrated circuits and the detectors can be integrated with readout circuits on one chip,resulting in a remarkable reduction in produce cost and a significant improvement of the imaging performance.2.The bilayer metasurface structure is used to reduce the reflection and increase the absorption of the BIB detector.The transmission and reflection of different epitaxial layers are measured by customizing the epitaxial BIB structure and other epitaxial layers.The optical parameters of different doping concentration epitaxial layers are obtained by using the Drude model.Combining the bilayer metasurface structure with the BIB device,the bilayer metasurface structure with polarizer has no observable transmission in the peak response band of the epitaxial Si:P BIB detector,and the reflectivity is less than 3%.The polarization information obtained by the detector conforms to the development trend of the fourth generation focal plane arrays.3.The cryogenic readout circuits are designed and the chip is made.The basic structure of readout circuits including operational amplifier are fabricated,and the cryogenic temperature characteristics of some circuits are tested and analyzed.The test and analysis lays a foundation for the further investigation into the readout circuits used for focal plane arrays working at cryogenic temperature.