As a result, the electric field in the absorption should be less than the tunneling threshold value to maintain the high field in the multiplication layer and the low dark current when the device avalanche breaks down.
When doping level of charge layer exceeds 2.0 × 1017 cm−3, the field in the absorption layer becomes lower than the tunneling threshold field, and the avalanche field in the multiplication layer reaches the same value with different doping level.
When the charge layer doping level exceeds 2.0 × 1017 cm−3, the field in the absorption layer becomes lower than the tunneling threshold field and the avalanche field in the multiplication layer reaches the same value.
Thus, the electric field in the absorption should be less than the tunneling threshold value to maintain the high field in the multiplication layer when the device avalanche breaks down.
In this paper, we study the effect of the charge layer and multiplication layer on the operating voltage ranges of APD and analyze the results theoretically from the internal electric field distribution.
However, when the doping level is less than 2.0 × 1017 cm−3, the field in the absorption layer exceeds the tunneling threshold field and the avalanche field in the multiplication layer decreases with the decrease of the doping level in charge layer.
In this paper, we report a two-dimensional (2D) simulation for InGaAs/InAlAs separate absorption, grading, charge, and multiplication avalanche photodiodes (SAGCM APDs) and study the effect of the charge layer and multiplication layer on the operating voltage ranges of APD.
The SAGCM structure allows independent control of the parameters of the charge layer and the multiplication layer (thickness and the doping concentration).
The electric field in the multiplication layer is enhanced by the charge layer to ensure the multiplication effect occurs in the multiplication layer.
With the increasing thickness and the doping of charge layer, the electric field in the absorption layer and the grading layer decreases, and it makes the electron more difficult to punch through the layers, so the punchthrough voltage increases, but the electric field in multiplication layer increases with the increased thickness and the doping of charge layer.
