Fig. 1. Schematic diagram of three-dimensional structure of P⁺/N well/deep N well SPAD device

Fig. 2. Movement process of photogenerated electron-hole pair

Fig. 3. Realization process of PDP modeling

Fig. 4. Simulated 2D electric field distribution of P⁺/N-well/deep N-well SPAD under 1 V overbias

Fig. 5. Electric field distribution obtained by Sentaurus Sdevice simulation under 1 V overbias

Fig. 6. Avalanche triggering probabilities of electron and hole at depletion region location x. (a) Avalanche triggering probability of electron; (b) avalanche triggering probability of hole; (c) total avalanche triggering probability of electron or hole

Fig. 7. Transmission spectrum of silica film

Fig. 8. PDP contributed by neutral region (P), neutral region (N), and depletion region

Fig. 9. Simulation results of PDP

Fig. 10. Simulated and measured PDP under 0.5 V overbias