摘要 |
<p>A deep SPAD structure uses the substrate as the anode terminal of its multiplication p-n junction. A bias voltage for the SPAD (in excess of the SPAD's breakdown voltage) is coupled to the SPAD's cathode terminal. The bias voltage is generated by a charge pump circuit which is also integrated on the substrate. The charge pump circuit is configured to isolate the bias voltage on the cathode terminal. A triple well CMOS process is used to isolate the transistors of the charge pump circuit from the substrate.</p> |