# US 12,218,260 B2 · Optical sensing device having inclined reflective surface

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- Number: US 12,218,260 B2
- Document ID: US12218260B2
- Status: Granted
- Kind: B2
- Application number: 17/874,276
- Filed: 2022-07-26
- Published: 2022-11-17
- Granted: 2025-02-04
- Earliest claimed: 2020-11-13
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chih-Chiang Chang; Chia-Chan Chen
- Web page: https://patentgrep.com/patent/US12218260B2

## CPC

- H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)}
- H10F 30/221: the potential barrier being a PN homojunction
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 77/147: {Shapes of bodies}
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Disclosed are devices for optical sensing and manufacturing method thereof. In one embodiment, a device for optical sensing includes a substrate, a photodetector and a reflector. The photodetector is disposed in the substrate. The reflector is disposed in the substrate and spaced apart from the photodetector, wherein the reflector has a reflective surface inclined relative to the photodetector that reflects light transmitted thereto to the photodetector.

## Claims

### Claim 1

A device for optical sensing, comprising:
a substrate comprising a trench;
a photodetector disposed in the substrate and next to the trench;
a first dielectric layer disposed on the substrate and comprising a through hole connected to the trench; and
a reflector disposed on the first dielectric layer and extending into the trench through a sidewall of the through hole, wherein the reflector exposes a side of the trench close to the photodetector.

### Claim 2 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein
the substrate is a semiconductor substrate,
the photodetector is a photodiode, and
the device for optical sensing further comprises an isolation element disposed in the substrate and surrounds the photodetector and the reflector.

### Claim 3 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein the trench has a first side and a second side located between the first side and the photodetector,
the reflector is disposed on the first side and exposes at least a portion of the second side.

### Claim 4 (depends on 3)

The device for optical sensing as claimed in claim 3, wherein the trench is V-shaped or U-shaped.

### Claim 5 (depends on 3)

The device for optical sensing as claimed in claim 3, further comprising:
a second dielectric layer disposed on the reflector and the first dielectric layer.

### Claim 6 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein spectral reflectivity of the reflector at wavelength less than 800 nm is larger than or equal to 0.4, and the spectral reflectivity of the reflector at wavelength greater than or equal to 800 nm is larger than or equal to 0.6.

### Claim 7 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein an inclination angle θ of a reflective surface of the reflector satisfies:
tan
⁡
(
2
⁢
θ
-
90
°
)
≤
TH
TH
×
cot
⁢
θ
+
2
⁢
D
wherein TH is a thickness of the reflector in the substrate, and D is a distance between the photodetector and the reflector.

### Claim 8 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein a distance D between the photodetector and the reflector satisfies:
D≤W1
wherein W1 is a width of the photodetector along an arrangement direction of the photodetector and the reflector.

### Claim 9 (depends on 1)

The device for optical sensing as claimed in claim 1, wherein an area AR of a reflective surface of the reflector satisfies:
AR≥½(W2×W3)
wherein W2 is a width of the photodetector along a direction perpendicular to a thickness direction of the photodetector and an arrangement direction of the photodetector and the reflector, and W3 is a width of the photodetector along the thickness direction of the photodetector.

### Claim 10

A device for optical sensing, comprising:
a substrate comprising a trench having symmetrical first and second sides;
a photodetector disposed in the substrate and next to the second side;
a first dielectric layer disposed on the substrate and comprising a through hole connected to the trench; and
a reflector disposed on and in contact with the first side of the trench and exposing a portion of the second side of the trench.

### Claim 11 (depends on 10)

The device for optical sensing as claimed in claim 10, wherein spectral reflectivity of the reflector at wavelength less than 800 nm is larger than or equal to 0.4, and the spectral reflectivity of the reflector at wavelength equal to or greater than 800 nm is larger than or equal to 0.6.

### Claim 12 (depends on 10)

The device for optical sensing as claimed in claim 10, wherein the trench is V-shaped or U-shaped, and an inclination angle θ of a reflective surface of the reflector satisfies:
tan
⁡
(
2
⁢
θ
-
90
°
)
≤
TH
TH
×
cot
⁢
θ
+
2
⁢
D
wherein TH is a thickness of the reflector in the substrate, and D is a distance between the photodetector and the reflector.