Multiplication characteristics of InP/InGaAs avalanche photodiodes with a thicker charge layer

We studied the multiplication performance of InP/InGaAs avalanche photodiode (APD) experimentally and theoretically, considering the electric field distribution, carrier concentration, and layers thickness. It has been found that ionization in the charge layer is very sensitive to avalanche multiplication (M) and breakdown voltage (Vbr). Partial ionization of charge layer has been suggested, which gives a good description of experimental results. C–V measurement is another way to estimate multiplication layer width (d4).