CMOS Geiger-mode avalanche photodiode detectors for time and intensity resolved measurements William G. Lawrence *a , Tani Tozian a , Christopher Stapels a , James F. Christian a , Gregory D. Derderian b , Jeffrey P. Derderian b , Gyula Varadi a a Radiation Monitoring Devices Inc. 44 Hunt St., Watertown MA 02472; b Dipole Engineering. 86 Bedford St, Boston MA 02111; ABSTRACT Geiger-mode avalanche photodiode detectors are produced using standard CMOS fabrication methods. We have produced integrated circuits that include the Geiger-mode photodetector and digital signal processing circuits. Our current design includes sixteen photon counting detector elements, with bias control, active quenching circuits, and integrated counters at each pixel. The detectors are used to measure chemiluminescence from horseradish peroxidase conjugated antibodies in sub-microliter samples using an optical waveguide. The detector array has been coupled with an external field programmable gate array (FPGA) to perform multi-channel, all digital, time resolved fluorescence measurements of quantum dot nanoparticles and the pH dependence of the fluorescence lifetime of fluorescein dye. Keywords: Chemiluminescence, photon counting, GPD, SPAD, TCSPC 1. INTRODUCTION In the last decade there has been significant growth in the development and application of single photon counting detectors fabricated using commercial complementary metal oxide semiconductor (CMOS) processes(1-6). Previously at RMD we have fabricated and tested such devices for applications in optical and nuclear detection systems(7-11). The CMOS detector components are inherently planar devices comprised of a shallow P-N junction with a guard ring structure to prevent edge breakdown(12). The guard ring is used to maintain a high operating voltage (15 – 85 V) across the diode junction. An initial electron – hole pair is generated when a photon with energy above 1.1 eV is incident on the photoactive area of the detector. Under sufficient bias, the electron hole pair is accelerated and the electron (or hole) will collide with the local lattice to produce additional charge carriers by impact ionization. The avalanche photodiode detector (APD) derives its name from the resulting avalanche of charge carriers. Geiger mode operation is observed when the detector is biased above the breakdown voltage of the junction. An incident photon produces a sustained avalanche of charge carriers that generates a discrete current pulse. This current pulse is a digital representation of a single incident photon. Geiger-mode photon-counting avalanche photodiodes produced using CMOS fabrication techniques have been referred to as GPDs (Geiger PhotoDiodes) and CMOS SPADs (Single Photon Avalanche photoDiodes). The use of CMOS fabrication processes to create the photon counting detectors has a number of advantages including the capacity to make high volumes of detectors at low cost with an existing manufacturing base. The GPD detector elements can be incorporated into more complex circuits for dedicated applications that require additional electronic components(13,14). These additional components can be integrated into the same die with the photodetector and there is an existing base of component design libraries or design intellectual property (IP). The discrete output of the individual photon detection signal from the GPD detector can be used to directly drive additional digital circuitry. Other specialized fabrication processes have been used to create planar photon counting detector devices for specific applications or for operation in different spectral regions(15-17). In this publication we will focus on the integration of additional electronic components with the GPD detector and investigate applications for these integrated devices in microanalytical systems. Lab-on-chip systems are designed to achieve high sensitivity detection of analytes in small sample volumes and optical detection methods provide some of MOEMS and Miniaturized Systems IX, edited by Harald Schenk, Wibool Piyawattanametha, Proc. of SPIE Vol. 7594, 75940I · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.839239 Proc. of SPIE Vol. 7594 75940I-1