A cmos APD optoelectronic device with low dark current

Abstract

The invention claims a CMOS APD photoelectric device with low dark current, which belongs to the field of semiconductor photoelectric devices. The device structure includes a P substrate, which also includes a P well on which ions are implanted, and the ion implantation on the P well has one N+ layer and two P+ layers, the N+ layer is a cathode, and the P+ layer is an anode. The heavily doped N+ layer and the lightly doped P well layer form a PN junction, that is, an avalanche region is formed, and an illumination window is set. When the light source enters the device and is absorbed by the light absorption region, photogenerated carriers are generated. Carriers move to the avalanche region under the action of an electric field to participate in multiplication; the two ends of the gap of the P well layer are also doped with STI guard rings and the two sides of the N+ layer are doped with small-sized STI guard rings. The reasonable setting of STI can ensure The reduction of the dark current can also enable the photocurrent to be detected effectively; the photoelectric effect and capacitance are optimized in the design of the device electrode. This design technology is designed from three aspects: PN junction, STI guard ring, and electrode setting to reduce the dark current of the device, ensure that the photocurrent can be detected, and the capacitance is reduced.

Description

technical field [0001] The invention belongs to the field of semiconductor devices, relates to the design technology design of APD optoelectronic devices, and in particular relates to the design of a low dark current CMOS APD optoelectronic device. Background technique [0002] Avalanche Photodiode is a photodetector capable of achieving high sensitivity and high bandwidth. It has the function of generating multiplied carrier electrons and holes by utilizing the avalanche breakdown effect to absorb the optical signal in the depletion layer. The basic design technology of CMOS APD is similar to the basic design technology of ordinary PN junction, but new design technology is adopted in the device structure design, which can effectively improve the working bandwidth of the device and reduce the dark current of the device. CMOSAPDs operating in the linear region are widely used in the Internet of Things, compact disc read only memory (CD-ROM), digital versatile disc (DVD) and ...

AI Technical Summary

Problems solved by technology

The traditional APD device design technology will add STI protection ring optimization on both sides of the cathode and anode, ignoring the drift distance of photogenerated electron carriers and the reasonable use of STI protection ring, so it cannot guarantee the detection of weak photocurrent. down, while maintaining a relatively low dark current

Images