# US 2025/0098296 A1 · Integrated circuit with latch-up immunity

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- Number: US 2025/0098296 A1
- Document ID: US20250098296A1
- Status: Published application
- Kind: A1
- Application number: 18/961,566
- Filed: 2024-11-27
- Published: 2025-03-20
- Earliest claimed: 2020-02-24
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Jing-Yi Lin; Chih-Chuan Yang; Shih-Hao Lin
- Web page: https://patentgrep.com/patent/US20250098296A1

## CPC

- H10D 84/0191: {Manufacturing their doped wells}
- H10D 84/856: {the complementary IGFETs having different architectures than each other, e.g. high-voltage and low-voltage CMOS}
- H10D 84/0193: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/853: {comprising FinFETs}
- H10D 84/854: {comprising arrangements for preventing bipolar actions between the different IGFET regions, e.g. arrangements for latchup prevention}
- H10D 89/931: {characterised by the dispositions of the protective arrangements}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Various embodiments of the present disclosure are directed towards a method for forming an integrated chip. The method includes forming an epitaxial structure having a first doping type over a first portion of a semiconductor substrate. A second portion of the semiconductor substrate is formed over the epitaxial structure and the first portion of the semiconductor substrate. A first doped region having the first doping type is formed in the second portion of the semiconductor substrate and directly over the epitaxial structure. A second doped region having a second doping type opposite the first doping type is formed in the second portion of the semiconductor substrate, where the second doped region is formed on a side of the epitaxial structure. A plurality of fins of the semiconductor substrate are formed by selectively removing portions of the second portion of the semiconductor substrate.

## Claims

### Claim 1

An integrated chip (IC), the IC comprising:
a semiconductor substrate having a first surface and a second surface, wherein the first surface is opposite the second surface;
a first semiconductor fin protruding from the first surface;
a second semiconductor fin protruding from the first surface, wherein the second semiconductor fin is spaced from the first semiconductor fin, and wherein the first surface extends laterally between the first semiconductor fin and the second semiconductor fin;
a first doped region disposed in the semiconductor substrate, wherein the first doped region has a first doping type, and wherein the first semiconductor fin is disposed within a perimeter of the first doped region;
a second doped region disposed in the semiconductor substrate, wherein the second doped region has a second doping type opposite the first doping type, and wherein the second semiconductor fin is disposed within a perimeter of the second doped region; and
an epitaxial structure disposed in the semiconductor substrate, wherein the epitaxial structure has the first doping type, wherein the first doped region overlies the epitaxial structure, wherein the first semiconductor fin overlies the epitaxial structure, wherein the epitaxial structure is disposed vertically between the first surface and the second surface of the semiconductor substrate, and wherein the epitaxial structure is vertically spaced from the first surface of the semiconductor substrate.

### Claim 2 (depends on 1)

The IC of claim 1, wherein the first doped region and the second doped region meet at a p-n junction arranged between the first semiconductor fin and the second semiconductor fin.

### Claim 3 (depends on 2)

The IC of claim 2, further comprising:
an isolation region of dielectric material laterally separating the first semiconductor fin and the second semiconductor fin, wherein the first doped region, the second doped region, and the epitaxial structure each at least partially underlie the isolation region.

### Claim 4 (depends on 1)

The IC of claim 1, further comprising:
a conductive gate electrode extending continuously over the first semiconductor fin and the second semiconductor fin; and
a gate dielectric separating the conductive gate electrode from the first semiconductor fin and the second semiconductor fin.

### Claim 5 (depends on 1)

The IC of claim 1, wherein:
the epitaxial structure has a thickness;
a lower surface of the epitaxial structure is spaced from the lower surface of the semiconductor substrate by a distance; and
a ratio of the thickness to the distance is between 1:200 and 1:800.

### Claim 6 (depends on 1)

The IC of claim 1, wherein:
the first semiconductor fin has a height;
the epitaxial structure has a thickness; and
a ratio of the height to the thickness is between 1:10 and 1:600.

### Claim 7

An integrated chip (IC), the IC comprising:
a semiconductor substrate having a first surface and a second surface, wherein the first surface is opposite the second surface;
a first semiconductor fin over the first surface;
a second semiconductor fin over the first surface, wherein the second semiconductor fin is spaced from the first semiconductor fin, and wherein the first surface extends laterally between the first semiconductor fin and the second semiconductor fin;
a first doped region disposed in the semiconductor substrate, wherein the first doped region has a first doping type, and wherein the first semiconductor fin is disposed within a perimeter of the first doped region;
a second doped region disposed in the semiconductor substrate, wherein the second doped region has a second doping type opposite the first doping type, and wherein the second semiconductor fin is disposed within a perimeter of the second doped region; and
a third doped region disposed in the semiconductor substrate, wherein the third doped region has the first doping type, wherein the first doped region overlies the third doped region, wherein the first semiconductor fin overlies the third doped region, wherein the third doped region is disposed vertically between the first surface and the second surface of the semiconductor substrate, and wherein the third doped region is vertically spaced from the first surface of the semiconductor substrate.

### Claim 8 (depends on 7)

The IC of claim 7, further comprising:
a conductive gate electrode extending continuously over the first semiconductor fin and the second semiconductor fin; and
a gate dielectric separating the conductive gate electrode from the first semiconductor fin and the second semiconductor fin.

### Claim 9 (depends on 7)

The IC of claim 7, wherein:
the first doped region is disposed in a lower portion of the first semiconductor fin; and
the second doped region is disposed in a lower portion of the second semiconductor fin.

### Claim 10 (depends on 9)

The IC of claim 9, further comprising:
a pair of fourth doped regions disposed in an upper portion of the first semiconductor fin, the pair of fourth doped regions spaced laterally apart from one another in the first semiconductor fin by a first body region that laterally separates the pair of fourth doped regions from one another; and
a pair of fifth doped regions disposed in an upper portion of the second semiconductor fin, the pair of fifth doped regions spaced laterally apart from one another in the second semiconductor fin by a second body region that laterally separates the pair of fifth doped regions from one another.

### Claim 11 (depends on 10)

The IC of claim 10, further comprising:
a conductive gate electrode extending continuously over the first body region of the first semiconductor fin and over the second body region of the second semiconductor fin; and
a gate dielectric separating the conductive gate electrode from the first body region and the second body region.

### Claim 12 (depends on 11)

The IC of claim 11, further comprising:
an isolation region of dielectric material laterally separating the first semiconductor fin and the second semiconductor fin, wherein the first doped region, the second doped region, and the third doped region each at least partially underlie the isolation region.

### Claim 13 (depends on 12)

The IC of claim 12, wherein the first and second doped regions meet at a p-n junction, and the third doped region has an edge that is aligned with the p-n junction.

### Claim 14 (depends on 13)

The IC of claim 13, wherein the edge of the third doped region and the p-n junction are directly under the isolation region.

### Claim 15 (depends on 7)

The IC of claim 7, wherein the first semiconductor fin is a nearest neighbor with the second semiconductor fin in that no other semiconductor fins are arranged between the first semiconductor fin and the second semiconductor fin.

### Claim 16 (depends on 7)

The IC of claim 7, further comprising:
an additional semiconductor fin arranged between the first semiconductor fin and the second semiconductor fin.

### Claim 17

A method for forming an integrated chip (IC), the method comprising:
receiving a first portion of a semiconductor substrate, wherein the first portion of the semiconductor substrate has a first region and has a second region disposed on a first side of the first region of the first portion of the semiconductor substrate;
forming an epitaxial structure having a first doping type over the first region of the first portion of the semiconductor substrate;
forming a second portion of the semiconductor substrate over the epitaxial structure and over the first portion of the semiconductor substrate, wherein the second portion of the semiconductor substrate has a first region that overlies the epitaxial structure and overlies the first region of the first portion of the semiconductor substrate, and wherein the second portion of the semiconductor substrate has a second region that overlies the second region of the first portion of the semiconductor substrate;
forming a first doped region having the first doping type in the first region of the second portion of the semiconductor substrate;
forming a second doped region having a second doping type opposite the first doping type in the second region of the second portion of the semiconductor substrate;
forming a first fin of the semiconductor substrate over the epitaxial structure by selectively removing portions of the first region of the second portion of the semiconductor substrate; and
forming a second fin of the semiconductor substrate over the second region of the first portion of the semiconductor substrate by selectively removing portions of the second region of the second portion of the semiconductor substrate, wherein the first fin and the second fin are laterally spaced.

### Claim 18 (depends on 17)

The method of claim 17, wherein forming the epitaxial structure comprises:
growing an epitaxial layer on an upper surface of the first portion of the semiconductor substrate via an epitaxial process, wherein the epitaxial layer is formed as a continuous layer that extends across both the first region of the first portion of the semiconductor substrate and the second region of the first portion of the semiconductor substrate;
forming a patterned masking layer on the epitaxial layer that covers a third portion of the epitaxial layer, wherein the third portion of the epitaxial layer is disposed directly over the first region of the first portion of the semiconductor substrate; and
with the patterned masking layer in place, removing a fourth portion of the epitaxial layer that is disposed directly over the second region of the first portion of the semiconductor substrate, thereby leaving the third portion of the epitaxial layer in place as the epitaxial structure.

### Claim 19 (depends on 18)

The method of claim 18, wherein the epitaxial layer is in-situ doped with first doping type dopants during the epitaxial process, such that the epitaxial layer has a first doping concentration of the first doping type.

### Claim 20 (depends on 17)

The method of claim 17, wherein:
wherein the epitaxial structure has a first doping concentration of the first doping type;
wherein the first doped region has a second doping concentration of the first doping type; and
a ratio of the first doping concentration to the second doping concentration is between 10:1 and 1000:1.