# US 12,222,542 B2 · Photonic device on a semiconductor-on-insulator substrate and method of manufacturing thereof

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- Number: US 12,222,542 B2
- Document ID: US12222542B2
- Status: Granted
- Kind: B2
- Application number: 17/560,001
- Filed: 2021-12-22
- Published: 2022-10-27
- Granted: 2025-02-11
- Earliest claimed: 2021-04-23
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Yueh Ying Lee; Tzu-Chung Tsai; Chien-Ying Wu; Jhih-Ming Lin
- Web page: https://patentgrep.com/patent/US12222542B2

## CPC

- G02B 6/122: Basic optical elements, e.g. light-guiding paths
- H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)}
- G02B 6/136: by etching
- H10F 77/206: {for devices having potential barriers}
- G02B 6/12004: {Combinations of two or more optical elements}
- G02B 6/30: for use between fibre and thin-film device
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A method of fabricating a photonic device includes: forming a photonic device structure that includes a SOI substrate, which includes a bulk substrate layer, a buried oxide layer on the bulk substrate layer and an active semiconductor layer on the buried oxide layer; forming an electrically conducting layer in electrical contact of the buried oxide layer, and forming a BEOL structure on a surface of the active silicon layer.

## Claims

### Claim 1

A method of fabricating a photonic device comprising:
forming a photonic device structure comprising a SOI substrate, wherein the SOI substrate comprises a bulk substrate layer, a buried oxide layer on the bulk substrate layer and an active semiconductor layer on the buried oxide layer;
forming an electrically conducting layer in electrical contact with the buried oxide layer; and
forming a BEOL structure on a surface of the active semiconductor layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the photonic device structure comprises an optical waveguide patterned in the active semiconductor layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the photonic device structure comprises an optical detector patterned in the active semiconductor layer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the electrically conducting layer comprises a doped conducting polymer.

### Claim 5 (depends on 4)

The method of claim 4, wherein the electrically conducting layer comprises doped polyaniline.

### Claim 6 (depends on 1)

The method of claim 1, further comprising placing the photonic device structure with the formed electrically conducting layer into an electrically conducting holder, so that the electrically conducting holder has an electrical contact with the electrically conducting layer.

### Claim 7 (depends on 6)

The method of claim 6, further comprising modifying the photonic device structure placed into the electrically conducting holder, wherein said modifying introduces a static electric charge in the buried oxide layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein said modifying comprises etching one or more insulating layer(s) in the BEOL structure.

### Claim 9 (depends on 7)

The method of claim 7, wherein the photonic device structure comprises an optical waveguide patterned in the active semiconductor layer and said modifying comprises etching a trench through insulating layers of the BEOL structure towards the optical waveguide.

### Claim 10 (depends on 9)

The method of claim 9, further comprising filling the trench with a fiber optic material.

### Claim 11 (depends on 6)

The method of claim 6, further comprising performing electron microscopy on the photonic device structure placed into the electrically conducting holder.

### Claim 12 (depends on 1)

The method of claim 1, further comprising removing at least a portion of the bulk substrate layer.

### Claim 13

A method of fabricating a photonic device comprising:
forming a photonic device structure comprising:
an SOI substrate, wherein the SOI substrate comprises a bulk substrate layer, a buried oxide layer on the bulk substrate layer and an active semiconductor layer on the buried oxide layer;
an electrically conducting layer in electrical contact with the buried oxide layer;
a BEOL structure on a surface of the active silicon layer; and
placing the formed photonic structure into an electrically conducting holder so that the electrically conducting holder has an electrical contact with the electrically conducting layer.

### Claim 14 (depends on 13)

The method of claim 13, further comprising one or more of performing electron microscopy on the photonic device structure placed into the electrically conducting holder and modifying the photonic device structure placed into the electrically conducting holder.

### Claim 15 (depends on 3)

The method of claim 3, wherein the optical detector is a Si detector or a Ge detector.

### Claim 16 (depends on 1)

The method of claim 1, wherein the electrically conducting layer comprises doped silicon.

### Claim 17 (depends on 2)

The method of claim 2, further comprising forming the optical waveguide by implanting the active semiconductor layer with impurities.

### Claim 18 (depends on 2)

The method of claim 2, wherein a thickness of the buried oxide layer is at least 2 times less than a wavelength of light used by the waveguide.

### Claim 19 (depends on 1)

The method of claim 1, wherein the electrically conducting layer has a conductivity of at least 1×10−3 S/cm.

### Claim 20 (depends on 1)

The method of claim 1, wherein the electrically conducting layer has a thickness from 1 μm to 1000 μm.