US-20260129980-A1 - LAYERED AVALANCHE DETECTOR

US20260129980A1US 20260129980 A1US20260129980 A1US 20260129980A1US-20260129980-A1

Abstract

An avalanche photodiode device includes a first doped layer having a first doping type, a second doped layer having a second doping type, a third doped layer having the first doping type, a first PN junction between the first doped layer and the second doped layer, a second PN junction between the second doped layer and the third doped layer, a first vertical conductive structure coupled to the first doped layer and the third doped layer, and a second vertical conductive structure coupled to the second doped layer.

Inventors

Francesco GRAMUGLIA
Eng Huat Toh

Assignees

GLOBALFOUNDRIES SINGAPORE PTE. LTD.

Dates

Publication Date: 20260507
Application Date: 20241107

Claims (20)

1 . An avalanche photodiode device comprising: a first doped layer having a first doping type; a second doped layer having a second doping type; a third doped layer having the first doping type; a first PN junction between the first doped layer and the second doped layer; a second PN junction between the second doped layer and the third doped layer; a first vertical conductive structure coupled to the first doped layer and the third doped layer; and a second vertical conductive structure coupled to the second doped layer.
2 . The avalanche photodiode device of claim 1 , wherein the first vertical conductive structure is a first trench structure and the second vertical conductive structure is a second trench structure.
3 . The avalanche photodiode device of claim 2 , wherein the first trench structure is coupled to two sides of the first and third doped layers, and the second trench structure is coupled to two sides of the second doped layer.
4 . The avalanche photodiode device of claim 1 , wherein one of the first and second conductive structures has a trench shape, and the other of the first and second conductive structures has a pillar shape.
5 . The avalanche photodiode device of claim 1 , wherein one of the first and second vertical conductive structures is an anode, and the other of the first and second vertical conductive structures is a cathode.
6 . The avalanche photodiode device of claim 1 , wherein the first and second conductive structures comprise doped sidewalls and a conductive material between the doped sidewalls.
7 . The avalanche photodiode device of claim 1 , further comprising: a fourth doped layer having the second doping type; and a third PN junction between the third doped layer and the fourth doped layer.
8 . The avalanche photodiode device of claim 7 , further comprising: a fifth doped layer coupled to the first vertical conductive structure; and a fourth PN junction between the fourth doped layer and the fifth doped layer.
9 . The avalanche photodiode device of claim 1 , further comprising: a guard ring between the first and second PN junctions and the first vertical conductive structure.
10 . The avalanche photodiode device of claim 1 , further comprising: a guard ring between uncoupled edges of the first and third doped layers and the second vertical conductive structure, and between uncoupled edges of the second doped layer and the first vertical conductive structure.
11 . The avalanche photodiode device of claim 1 , wherein sidewalls of the first and second vertical conductive structures have a dopant concentration on the order of from 10 18 /cm 3 to 10 19 /cm 3 , and the first, second, and third doped layers have a dopant concentration on the order of from 10 17 /cm 3 to 10 18 /cm 3 .
12 . A photodetector comprising at least one avalanche photodiode device, the at least one avalanche photodiode device comprising: a first doped layer having a first doping type; a second doped layer having a second doping type; a third doped layer having the first doping type; a first PN junction between the first doped layer and the second doped layer; a second PN junction between the second doped layer and the third doped layer; a first vertical conductive structure coupled to the first doped layer and the third doped layer; and a second vertical conductive structure coupled to the second doped layer.
13 . The photodetector of claim 12 , wherein the first vertical conductive structure is a first trench structure and the second vertical conductive structure is a second trench structure.
14 . The photodetector of claim 13 , wherein the first trench structure is coupled to at least two sides of the first and third doped layers, and the second trench structure is coupled to at least two sides of the second doped layer.
15 . The photodetector of claim 12 , wherein one of the first and second conductive structures has a trench shape, and the other of the first and second conductive structures has a pillar shape.
16 . The photodetector of claim 12 , wherein the first and second conductive structures comprise doped sidewalls and a conductive material between the doped sidewalls.
17 . The photodetector of claim 12 , wherein the at least one avalanche photodiode device further comprises: a fourth doped layer having the second doping type; and a third PN junction between the third doped layer and the fourth doped layer.
18 . The photodetector of claim 12 , wherein the at least one avalanche photodiode device further comprises: a guard ring between the first and second PN junctions and the first vertical conductive structure.
19 . The photodetector of claim 12 , wherein the at least one avalanche photodiode comprises an array of avalanche photodiodes, and at least two of the avalanche photodiodes in the array share the first vertical conductive structure as an anode or a cathode for the at least two avalanche photodiodes.
20 . A method for forming an avalanche photodiode device, the method comprising: forming a first doped layer having a first doping type; forming a second doped layer having a second doping type; forming a third doped layer having the first doping type; forming a first vertical conductive structure coupled to the first doped layer and the third doped layer; and forming a second vertical conductive structure coupled to the second doped layer and the fourth doped layer, wherein a first PN junction is located between the first doped layer and the second doped layer, and a second PN junction is located between the second doped layer and the third doped layer.

Description

BACKGROUND Photodetectors are sensors that detect the presence of electromagnetic radiation. Semiconductor photodiodes are a category of photodetectors that use a P-N diode to convert incident photons into current. Photodiodes are used by many different technologies to sense one or more frequency of light, to determine the time at which transmitted light is reflected back to the photodiode, etc. Avalanche photodiodes are a highly biased photodiodes in which photo-generated carriers are multiplied by avalanche breakdown in the device. Single-photon avalanche diodes (SPADs) are avalanche photodiodes which are sensitive enough to detect the incidence of a single photon, and have lower timing jitter than typical photodiodes. Conventional avalanche photodiodes tend to be relatively complex structures that are difficult to fabricate, and the layout of conventional photodiodes limits their fill factor. SUMMARY Embodiments of the present application relate to an avalanche photodiode (APD) device, a photodetector, and a method for forming an APD device. According to at least some of the embodiments disclosed herein, an avalanche photodiode device includes a first doped layer having a first doping type, a second doped layer having a second doping type, a third doped layer having the first doping type, a first PN junction between the first doped layer and the second doped layer, a second PN junction between the second doped layer and the third doped layer, a first vertical conductive structure coupled to the first doped layer and the third doped layer, and a second vertical conductive structure coupled to the second doped layer. According to at least some of the embodiments disclosed herein, a photodetector includes at least one avalanche photodiode device which comprises a first doped layer having a first doping type, a second doped layer having a second doping type, a third doped layer having the first doping type, a first PN junction between the first doped layer and the second doped layer, a second PN junction between the second doped layer and the third doped layer, a first vertical conductive structure coupled to the first doped layer and the third doped layer, and a second vertical conductive structure coupled to the second doped layer. According to at least some of the embodiments disclosed herein, a method for forming an avalanche photodiode device includes forming a first doped layer having a first doping type, forming a second doped layer having a second doping type, forming a third doped layer having the first doping type, forming a first vertical conductive structure coupled to the first doped layer and the third doped layer, and forming a second vertical conductive structure coupled to the second doped layer. A first PN junction is located between the first doped layer and the second doped layer and a second PN junction is located between the second doped layer and the third doped layer. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a plan view of an embodiment of an avalanche photodiode device. FIG. 2 is a cross-sectional view of the avalanche photodiode of FIG. 1. FIGS. 3A to 3F illustrate an embodiment of a process for forming the avalanche photodiode device of FIG. 2. FIG. 4 illustrates a plan view of an embodiment of an avalanche photodiode device with a pillar. FIG. 5 is a cross-sectional view of the avalanche photodiode of FIG. 4. FIG. 6 illustrates an embodiment of an avalanche photodiode array. FIG. 7 is a cross-sectional view of the avalanche photodiode array of FIG. 6. DETAILED DESCRIPTION A detailed description of embodiments is provided below along with accompanying figures. The scope of this disclosure is limited by the claims and encompasses numerous alternatives, modifications and equivalents. Although steps of various processes are presented in a given order, embodiments are not necessarily limited to being performed in the listed order. In some embodiments, certain operations may be performed simultaneously, in an order other than the described order, or not performed at all. Numerous specific details are set forth in the following description. These details are provided to promote a thorough understanding of the scope of this disclosure by way of specific examples, and embodiments may be practiced according to the claims without some of these specific details. Accordingly, the specific embodiments of this disclosure are illustrative, and are not intended to be exclusive or limiting. For the purpose of clarity, technical material that is known in the technical fields related to this disclosure has not been described in detail so that the disclosure is not unnecessarily obscured. The figures are not drawn to scale, and various features are enlarged or diminished for visual clarity. FIG. 1 illustrates a plan view of an avalanche photodiode (APD) device 100 according to an embodiment, and FIG. 2 illustrates a cross-sectional view of the APD device 100 taken along A-A′ of FIG. 1. The