Fig. 1. Schematic diagram of device structure: (a) schematic of cross-section of the fabricated SACM APD; (b) SEM image

Fig. 2. Schematic diagram of device structure simulation： (a) internal electric field of the device at different reverse biases，The inset shows the feedback electric field at the interface between electric field control layer and absorption layer; (b) simulated I-V characteristics and multiplication factor of the SACM APD; (c) energy band diagrams before punch-through; (d) energy band diagrams after punch-through; (e) doping concentration diagram of the device, when the ion implantation energy is 580 keV

Fig. 3. I-V characteristics of SACM APD and dark current characteristics of SACM APD with different sizes： (a) I-V characteristics and multiplication factor of 100 μm SACM APD; (b) the dark current curves of devices with photosensitive surface radii of 20 μm, 50 μm, 100 μm and 200 μm; (c) relationships between the dark current and the photosensitive area radius at -30 V, the red line is the fitting curve according to Eq. (1)

Fig. 4. I-V characteristics and spectral response of SACM APD： (a) I-V characteristics of 100 μm SACM APD with different input light wavelengths; (b) spectral response of 100 μm SACM APD at different reverse biases

Fig. 5. C-V characteristics of SACM APD：(a) C-V characteristics of 100μm SACM APD at 100 kHz,200 kHz,500 kHz,1 MHz and 5 MHz, respectively; (b) C-V characteristics of devices with different photosensitive surface radii at 1 MHz (dashed line represents the simulation result for devices with a radius of 100 μm at 1 MHz) ;(c) fitting relationships between the capacitance value and the device photosensitive area at 0 V, -20 V and -30 V bias

Fig. 6. Temperature characteristics of SACM APD： (a) dark current of 200 μm SACM APD versus voltage at different temperatures; (b) the relationship between dark current and temperature at -20 V and -30 V bias