Design and Verification of An Avalanche Photodiode Device for Rare Earth Fluorescence Detection

The gain and spectral response range of photodiodes are very important for rare earth fluorescence detection. However, traditional photodiodes do not have internal gain, which cannot meet the requirements of the above fields. Therefore, an avalanche photodiode is designed and manufactured based on 0.18 μm CMOS process in this paper. N+/P-Well forms the avalanche multiplication region of the device, which is used for the detection of external photons. N-Well is used as the guard ring of the device to prevent the breakdown of the side junction of N+/P-Well. In addition, the principle of the device is verified based on Technology-Computer-Aided-Design (TCAD) simulation. The test results show that the avalanche breakdown voltage of the device is 11.7 V. When the reverse bias voltage is 11.7V, the dark current of the device is 9.8 × 10
^-9
A, and the photocurrent of the device is 3.8 × 10
^-6
A. The current after the avalanche breakdown of the device is 1 mA. The spectral response range of the device is 400 nm-1000 nm, the peak is 470 nm, and the responsivity is 6.7 A/W.