The Research Of FLIM SPAD Image Sensors' Key Techniques

Fluorescence lifetime imaging microscopy(FLIM)is a powerful tool in biological research with advantages over traditional fluorescence sensing techniques that include reduced sensitivity to common experimental variabilities and relaxed requirements for optical filters.Nevertheless,inadequacies in conventional lifetime imaging instrumentation have prevented the technique from reaching its full potential.The integration of lifetime-measurement sensor arrays in complementary metal oxide semiconductor(CMOS)technologies,made possible by recent successes in the fabrication of CMOS single photon avalanche diode(SPAD),enables novel imaging capabilities and biosensing platforms.This thesis analyzes the working principle of the FLIM based on the Time Correlated Single Photon Counting(TCSPC)firstly.And then the basic structure and principle of SPAD is introduced.The modeling of dark count rate(DCR)and photon Detection Probability(PDP)is done based on the Geiger mode working principle.A corresponding device simulation method is proposed.According to the application characteristics of FLIM,a full parallel event driven readout technique for area array SPAD FLIM image sensors aiming at reducing the data rate of tradition SPAD FLIM image sensors is proposed.And then,high frame rate is possible to implement.Monte Carlo simulation is done in Matlab in terms of the pile-up effect induced by the readout method.The design of SPAD device structure test chip is done.And the chip is fabricated in a Dongbu 0.13?m 1P3 M CMOS image sensors process.This thesis proposes a 16×16 FLIM SPAD image sensor,and completes the design of key circuit block,such as quenching circuit,PLL,time to digital converter(TDC),readout circuit and timing circuit.The time resolution of TDCs is 97.6 ps and the quantization range is 100 ns.The readout frame rate is 10 Mfps,and the maximum imaging frame rate is 100 fps.The chip's output bandwidth is 720 MHz with an average power of 15 mW.