The Research Of High Performance New Ultraviolet Detector Structure And CMOS Readout Circuit

Ultraviolet (UV) detector is a device which can selectively absorb the light in UVspectral range, and convert the light signal into electrical signal. At present, ultravioletdetection system has some shortcomings, such as low sensitivity, low integration, hugevolume and high power consumption. In order to solve the disadvantages of UV detector,this thesis proceed from Physics of Semiconductor Devices, based on CMOS-processfeature and silicon based detector research foundation, studying the method to improvelight quantum efficiency, decrease noise, enhance weak light response sensitivity of newdetector structure. Adopting the research methods of physical modeling, computationalsimulation, structural design, technological design and device processing establish,propose and simulate the analytical model and circuit model of optics and electricitycharacter of UV photoelectric detector. Researching readout circuit for the proposed newdevice structure, proposed a readout circuit structure which has low power consumptionand can efficiently restrain dark current and noise.This paper is based on Key Projects in Hunan Province Department of Education “Theresearch of high performance new ultraviolet detector structure and CMOS readoutcircuit”. The detailed research content is shown below:Design new UV detector structure which including improving surface shape andoptimizing the match of different layer， so as to achieve light selective absorption andimprove the area of pn junction. Designed structures have been taped out for three timesbased on standard0.5μm CMOS Process, the structures have taped out concludeoctagon-shaped, interdigital-shaped, octagon-shaped which using edge breakdown, noguard-ring shaped, and so on. The optical response, avalanche property, response speed,response time have been tested.Simplifying octagon-UV-detector structure, for example, only consider one anode oronly consider a half of the symmetrical structure, and simulating the structure by SilvacoTCAD, analyzing the avalanche properties, optical response property, electricaldistribution, current density distribution. Simulating results can be used as guidance fortaping out.Established two-dimensional mathematical model based on lateral and vertical carrierdiffusion equation and one dimensional optical response model, the model is simulatedusing Matlab, the simulated results are compared with device simulated results and testing results, so as to verify the validity of the two-dimensional model.Researching CMOS read-out circuit; designed a cascade operational amplifier; thisoperational amplifier realized signal, which obtained by UV detector, read out; optimizedfeed-back resistance and capacitance, and have taped-out; realized the function of opticaldetecting and reading out of optical signal; the system have taped out. Testing work is notcompleted, and it need to be done.