# US 2026/0075853 A1 · Breakdown diodes and methods of making the same

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- Number: US 2026/0075853 A1
- Document ID: US20260075853A1
- Status: Published application
- Kind: A1
- Application number: 19/386,779
- Filed: 2025-11-12
- Published: 2026-03-12
- Earliest claimed: 2022-12-29
- Applicants: Texas Instruments Incorporated
- Inventors: Alexei Sadovnikov; Natalia Lavrovskaya; Archana Venugopal
- Web page: https://patentgrep.com/patent/US20260075853A1

## CPC

- H10D 8/25: Zener diodes
- H10D 8/022: {of Zener diodes}
- H10D 62/114: {PN junction isolations}
- H10D 62/60: Impurity distributions or concentrations
- H10D 64/112: {comprising multiple field plate segments}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Breakdown diodes and methods of making the same are described. Such a breakdown diode can be fabricated in a semiconductor substrate and have a junction configured to breakdown under a target reverse bias applied across the junctions. The junction is located below the surface of the substrate by a distance suitable for ameliorating mechanical stress impact to the reverse bias breakdown voltage of the junction. Moreover, the junction is located away from an interface causing noise issues.

## Claims

### Claim 1

A method, comprising:
forming a deep n-well in a substrate with a surface, the deep n-well surrounding a p-doped region of the substrate; and
forming a p-Zener portion of the p-doped region, wherein the p-Zener portion and the deep n-well forms a pn junction configured to breakdown under a target reverse bias across the pn junction.

### Claim 2 (depends on 1)

The method of claim 1, wherein the pn junction is located below the surface by a distance greater than or equal to 1 micron.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
forming a deep trench prior to forming the deep n-well, wherein forming the deep n-well includes implanting n-type dopant atoms on a sidewall of the deep trench.

### Claim 4 (depends on 3)

The method of claim 3, wherein the deep trench surrounds the p-doped region of the substrate.

### Claim 5 (depends on 1)

The method of claim 1, wherein the pn junction surrounds a footprint of the p-doped region of the substrate.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
forming a p-well of the p-doped region, the p-well coupled to the p-Zener portion; and
forming a p+ portion of the p-doped region, the p+ portion extended from the surface and coupled to the p-well.

### Claim 7 (depends on 6)

The method of claim 6, wherein:
the p-Zener portion includes a first concentration of p-type dopants;
the p-well includes a second concentration of the p-type dopants less than the first concentration; and
the p+ portion includes a third concentration of the p-type dopants greater than the first concentration.

### Claim 8 (depends on 6)

The method of claim 6, wherein:
the p-Zener portion is located at a first distance from the surface;
the p-well is located at a second distance from the surface less than the first distance; and
the p+ portion is located at a third distance from the surface less than the second distance.

### Claim 9 (depends on 6)

The method of claim 6, wherein:
a first footprint of the p-Zener portion includes a second footprint of the p-well; and
the second footprint of the p-well includes a third footprint of the p+ portion.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
forming an n-well coupled to the deep n-well; and
forming an n+ region extended from the surface and coupled to the n-well.

### Claim 11 (depends on 10)

The method of claim 10, wherein:
the deep n-well includes a first concentration of n-type dopants;
the n-well includes a second concentration of the n-type dopants less than the first concentration; and
the n+ region includes a third concentration of the n-type dopants greater than the first concentration.

### Claim 12 (depends on 10)

The method of claim 10, wherein:
the deep n-well is located at a first distance from the surface;
the n-well is located at a second distance from the surface less than the first distance; and
the n+ region is located at a third distance from the surface less than the second distance.

### Claim 13 (depends on 6)

The method of claim 6, wherein:
a first footprint of the deep n-well overlaps a second footprint of the n-well; and
the second footprint of the n-well includes a third footprint of the n+ region.

### Claim 14

A method, comprising:
forming a mask defining an orifice over a substrate with a surface;
adding p-type dopants in the substrate through the orifice, wherein the p-type dopants has a peak concentration at a first distance from the surface;
adding n-type dopants in the substrate through the orifice, wherein the n-type dopants has a peak concentration at a second distance from the surface less than the first distance; and
applying thermal energy to the substrate including the p-type and n-type dopants.

### Claim 15 (depends on 14)

The method of claim 14, wherein, as a result of applying the thermal energy, the n-type dopants forms a n-Zener portion of the substrate, and the p-type dopants forms a p-Zener portion of the substrate underneath the n-Zener portion.

### Claim 16 (depends on 15)

The method of claim 15, wherein the n-Zener portion and the p-Zener portion forms a pn junction located below the surface by a distance greater than or equal to 1 micron.

### Claim 17 (depends on 15)

The method of claim 15, wherein a footprint of the n-Zener portion includes a footprint of the p-Zener portion.

### Claim 18 (depends on 15)

The method of claim 15, further comprising:
forming a p-well of the substrate coupled to the p-Zener portion, wherein a footprint of the p-well includes a footprint of the p-Zener portion; and
forming a p+ portion of the substrate coupled to the p-well, wherein a footprint of the p+ portion is within the footprint of the p-well.

### Claim 19 (depends on 18)

The method of claim 18, wherein the p+ portion encircles the n-Zener portion.

### Claim 20 (depends on 18)

The method of claim 18, wherein the p-well is a first p-well of the substrate, the method further comprising:
forming a second p-well of the substrate coupled to the first p-well, wherein the second p-well encircles the n-Zener portion.

### Claim 21 (depends on 15)

The method of claim 15, further comprising:
forming an n+ portion of the substrate coupled to the n-Zener portion, wherein the n+ portion extends from the surface and a footprint of the n+ portion is within a footprint of the n-Zener portion.