# US 2021/0343884 A1 · Integrated Photodetector

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2021/0343884 A1
- Document ID: US20210343884A1
- Status: Published application
- Kind: A1
- Application number: 17/377,052
- Filed: 2021-07-15
- Published: 2021-11-04
- Earliest claimed: 2016-02-05
- Assignees: Texas Instruments Incorporated
- Applicants: Texas Instruments Incorporated
- Inventors: Debarshi Basu; Henry Litzmann Edwards; Ricky A. Jackson; Marco A. Gardner
- Web page: https://patentgrep.com/patent/US20210343884A1

## CPC

- H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)}
- G01J 1/02: Details
- G01J 1/0209: {Monolithic}
- G01J 1/0411: {using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction}
- G01J 1/42: using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10)
- H10F 30/221: the potential barrier being a PN homojunction
- H10W 90/00: Package configurations
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

An integrated circuit that includes a substrate, a photodiode, and a Fresnel structure. The photodiode is formed on the substrate, and it has a p-n junction. The Fresnel structure is formed above the photodiode, and it defines a focal zone that is positioned within a proximity of the p-n junction. In one aspect, the Fresnel structure may include a trench pattern that functions as a diffraction means for redirecting and concentrating incident photons to the focal zone. In another aspect, the Fresnel structure may include a wiring pattern that functions as a diffraction means for redirecting and concentrating incident photons to the focal zone. In yet another aspect, the Fresnel structure may include a transparent dielectric pattern that functions as a refractive means for redirecting and concentrating incident photons to the focal zone.

## Claims

### Claim 1

An integrated circuit, comprising:
a substrate;
a photodiode formed on the substrate, the photodiode having a p-n junction; and
a Fresnel structure formed above the photodiode, the Fresnel structure defining a focal zone positioned within a proximity of the p-n junction.

### Claim 2 (depends on 1)

The integrated circuit of claim 1, wherein the Fresnel structure includes a trench pattern formed above the photodiode, the trench pattern including:
a first trench positioned adjacent to a central region of the Fresnel structure by a first radial distance, the first trench having a first trench width based on a first difference between a second radial distance and the first radial distance; and
a second trench positioned adjacent to the central region of the Fresnel structure by a third radial distance, the second trench having a second trench width based on a second difference between a fourth radial distance and the third radial distance.

### Claim 3 (depends on 2)

The integrated circuit of claim 2, wherein:
the first radial distance is based on a focal length defined by the focal zone, a first multiplier, and a wavelength of an electromagnetic (EM) wave to be detected by the photodiode;
the second radial distance is based on the focal length, a second multiplier greater than the first multiplier, and the wavelength of the EM wave to be detected by the photodiode;
the third radial distance is based on the focal length, a third multiplier greater than the second multiplier, and the wavelength of the EM wave to be detected by the photodiode; and
the fourth radial distance is based on the focal length, a fourth multiplier greater than the third multiplier, and the wavelength of the EM wave to be detected by the photodiode.

### Claim 4 (depends on 2)

The integrated circuit of claim 2, wherein:
the first trench includes a first ring trench parallel to a top surface of the substrate and laterally surrounding the central region of the Fresnel structure; and
the second trench includes a second ring trench parallel to the top surface of the substrate and laterally surrounding the first ring trench.

### Claim 5 (depends on 4)

The integrated circuit of claim 4, wherein:
the first ring trench includes a first circular ring trench having a center overlapping with the central region of the Fresnel structure; and
the second ring trench includes a second circular ring trench concentric with the first circular ring trench.

### Claim 6 (depends on 4)

The integrated circuit of claim 4, wherein:
the first ring trench includes a first octagonal ring trench having a center overlapping with the central region of the Fresnel structure; and
the second ring trench includes a second octagonal ring trench concentric with the first octagonal ring trench.

### Claim 7 (depends on 4)

The integrated circuit of claim 4, wherein:
the first ring trench includes a first rectangular ring trench having a center overlapping with the central region of the Fresnel structure; and
the second ring trench includes a second rectangular ring trench concentric with the first rectangular ring trench.

### Claim 8 (depends on 2)

The integrated circuit of claim 2, wherein:
the first trench includes a first pair of parallel trenches placed on opposite sides of the central region of the Fresnel structure; and
the second trench includes a second pair of parallel trenches bracketing the first pair of parallel trenches.

### Claim 9 (depends on 2)

The integrated circuit of claim 2, wherein:
the first trench is etched into a top surface of the substrate; and
the second trench is etched into the top surface of the substrate.

### Claim 10 (depends on 2)

The integrated circuit of claim 2, wherein:
the first trench is etched into an epitaxial layer grown above the substrate; and
the second trench is etched into the epitaxial layer grown above the substrate.

### Claim 11 (depends on 2)

The integrated circuit of claim 2, wherein the Fresnel structure includes:
a first transparent dielectric structure occupying the first trench; and
a second transparent dielectric structure occupying the second trench.

### Claim 12 (depends on 1)

The integrated circuit of claim 1, wherein the Fresnel structure includes a wiring pattern formed above the photodiode, the wiring pattern including:
a first zone plate formed in a wiring layer above the substrate, the first zone plate positioned adjacent to a central region of the Fresnel structure by a first radial distance, the first zone plate having a first width based on a first difference between a second radial distance and the first radial distance; and
a second zone plate formed in the wiring layer and positioned adjacent to the central region of the Fresnel structure by a third radial distance, the second zone plate having a second width based on a second difference between a fourth radial distance and the third radial distance.

### Claim 13 (depends on 12)

The integrated circuit of claim 12, wherein the wiring layer includes a polysilicon layer formed on a dielectric layer above the substrate.

### Claim 14 (depends on 12)

The integrated circuit of claim 12, wherein the wiring layer includes a metal layer formed on a dielectric layer above the substrate.

### Claim 15 (depends on 12)

The integrated circuit of claim 12, wherein:
the first radial distance is based on a focal length defined by the focal zone, a first multiplier, and a wavelength of an electromagnetic (EM) wave to be detected by the photodiode;
the second radial distance is based on the focal length, a second multiplier greater than the first multiplier, and the wavelength of the EM wave to be detected by the photodiode;
the third radial distance is based on the focal length, a third multiplier greater than the second multiplier, and the wavelength of the EM wave to be detected by the photodiode; and
the fourth radial distance is based on the focal length, a fourth multiplier greater than the third multiplier, and the wavelength of the EM wave to be detected by the photodiode.

### Claim 16 (depends on 12)

The integrated circuit of claim 12, wherein:
the first zone plate includes a first ring plate parallel to a top surface of the substrate and laterally surrounding the central region of the Fresnel structure; and
the second zone plate includes a second ring plate parallel to the top surface of the substrate and laterally surrounding the first ring plate.

### Claim 17 (depends on 16)

The integrated circuit of claim 16, wherein:
the first ring plate includes a first circular ring plate having a center overlapping with the central region of the Fresnel structure; and
the second ring plate includes a second circular ring plate concentric with the first circular ring plate.

### Claim 18 (depends on 16)

The integrated circuit of claim 16, wherein:
the first ring plate includes a first octagonal ring plate having a center overlapping with the central region of the Fresnel structure; and
the second ring plate includes a second octagonal ring plate concentric with the first octagonal ring plate.

### Claim 19 (depends on 16)

The integrated circuit of claim 16, wherein:
the first ring plate includes a first rectangular ring plate having a center overlapping with the central region of the Fresnel structure; and
the second ring plate includes a second rectangular ring plate concentric with the first rectangular ring plate.

### Claim 20 (depends on 16)

The integrated circuit of claim 16, wherein:
the first zone plate includes a first pair of parallel plates placed on opposite sides of the central region of the Fresnel structure; and
the second zone plate includes a second pair of parallel plates bracketing the first pair of parallel plates.

### Claim 21

An integrated circuit, comprising:
a substrate;
a top surface positioned above the substrate;
a photodiode formed on the substrate, the photodiode having a p-n junction; and
a diffractive structure formed above the photodiode and beneath the top surface, the diffractive structure positioned to direct an electromagnetic (EM) wave from the top surface to a focal zone within a proximity of the p-n junction.

### Claim 22 (depends on 21)

The integrated circuit of claim 21, wherein the diffractive structure defines a slit pattern positioned above the photodiode, the slit pattern including:
a first slit positioned adjacent to a central region of the diffractive structure by a first radial distance, the first slit having a first slit width based on a first difference between a second radial distance and the first radial distance; and
a second slit positioned adjacent to the central region of the diffractive structure by a third radial distance, the second slit having a second slit width based on a second difference between a fourth radial distance and the third radial distance.

### Claim 23 (depends on 22)

The integrated circuit of claim 22, wherein:
the first radial distance is based on a focal length defined by the focal zone, a first multiplier, and a wavelength of the EM wave;
the second radial distance is based on the focal length, a second multiplier greater than the first multiplier, and the wavelength of the EM wave;
the third radial distance is based on the focal length, a third multiplier greater than the second multiplier, and the wavelength of the EM wave; and
the fourth radial distance is based on the focal length, a fourth multiplier greater than the third multiplier, and the wavelength of the EM wave.

### Claim 24 (depends on 22)

The integrated circuit of claim 22, wherein:
the first slit includes a first ring slit parallel to the top surface and laterally surrounding the central region of the diffractive structure; and
the second slit includes a second ring slit parallel to the top surface and laterally surrounding the first ring slit.

### Claim 25 (depends on 24)

The integrated circuit of claim 24, wherein:
the first ring slit includes a first circular ring slit having a center overlapping with the central region of the diffractive structure; and
the second ring slit includes a second circular ring slit concentric with the first circular ring slit.

### Claim 26 (depends on 24)

The integrated circuit of claim 24, wherein:
the first ring slit includes a first octagonal ring slit having a center overlapping with the central region of the diffractive structure; and
the second ring slit includes a second octagonal ring slit concentric with the first octagonal ring slit.

### Claim 27 (depends on 24)

The integrated circuit of claim 24, wherein:
the first ring slit includes a first rectangular ring slit having a center overlapping with the central region of the diffractive structure; and
the second ring slit includes a second rectangular ring slit concentric with the first rectangular ring slit.

### Claim 28 (depends on 22)

The integrated circuit of claim 22, wherein:
the first slit includes a first pair of parallel slits placed on opposite sides of the central region of the diffractive structure; and
the second slit includes a second pair of parallel slits bracketing the first pair of parallel slits.

### Claim 29 (depends on 21)

The integrated circuit of claim 21, wherein the diffractive structure includes shallow trenches etched into a top epitaxial layer grown above the substrate.

### Claim 30 (depends on 21)

The integrated circuit of claim 21, wherein the diffractive structure includes wire gratings formed in an interconnect layer.