# US 10,483,128 B2 · Epitaxially coated semiconductor wafer, and method for producing an epitaxially coated semiconductor wafer

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- Number: US 10,483,128 B2
- Document ID: US10483128B2
- Status: Granted
- Kind: B2
- Application number: 15/545,541
- Filed: 2015-10-29
- Published: 2018-02-15
- Granted: 2019-11-19
- Earliest claimed: 2015-01-21
- Assignees: Siltronic AG
- Applicants: Siltronic AG
- Inventors: Timo Mueller; Michael Gehmlich; Frank Faller
- Web page: https://patentgrep.com/patent/US10483128B2

## CPC

- H10P 36/20: Intrinsic gettering, i.e. thermally inducing defects by using oxygen present in the silicon body
- B08B 3/08: the liquid having chemical or dissolving effect
- C30B 25/20: the substrate being of the same materials as the epitaxial layer
- C30B 29/06: Silicon
- C30B 33/10: in solutions or melts
- H10D 62/53: the imperfections being within the semiconductor body
- H10D 62/83: being Group IV materials, e.g. B-doped Si or undoped Ge
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/3411: {Silicon, silicon germanium or germanium}
- H10P 14/6318: {Formation by simultaneous oxidation and nitridation}
- H10P 14/6927: {the material being a silicon oxynitride, e.g. SiON or SiON:H}
- H10P 52/402: {of semiconductor materials}
- H10P 70/15: {by wet cleaning only (H10P70/52 takes precedence)}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B08B: CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Epitaxial wafers with a high concentration of BMD nuclei or developed BMDs just below a denuded zone, and having low surface roughness, are produced by forming an oxynitride layer on a purposefully oxidized epitaxial layer by a short RTA treatment in a nitriding atmosphere, removing the oxynitride layer, and then polishing the epitaxial surface.

## Claims

### Claim 1

An epitaxially coated semiconductor wafer, comprising:
a substrate wafer comprising monocrystalline silicon having a front side, rear side, a center, and a periphery;
an epitaxial layer comprising silicon and having a polished surface on the front side of the substrate wafer, wherein the polished surface has an RMS roughness of not more than 0.055 nm in a measurement window having dimensions of 10 μm×10 μm;
a denuded zone extending from the polished surface of the epitaxial layer to the rear side of the substrate wafer as far as a depth which, between the center and the periphery of the semiconductor wafer, is not less than 6 μm and not more than 14 μm, and
a region adjoining the denuded zone and having BMD nuclei which can develop into BMDs by heat treatment, with a peak density of BMD nuclei of not less than 3.5×109 cm−3 at a distance of not more than 70 μm from the polished surface of the epitaxial layer.

### Claim 2 (depends on 1)

The epitaxially coated semiconductor wafer of claim 1, which has BMD nuclei which can develop into BMDs whose density at a distance of 50 μm from the polished surface of the epitaxial layer is not less than 70% of the peak density.

### Claim 3 (depends on 1)

The epitaxially coated semiconductor wafer of claim 1, which has BMD nuclei which can develop into BMDs whose density at a distance of 200 μm from the polished surface of the epitaxial layer as far as the rear side of the substrate wafer is not greater than 60% of the peak density.

### Claim 4 (depends on 2)

The epitaxially coated semiconductor wafer of claim 2, which has BMD nuclei which can develop into BMDs whose density at a distance of 200 μm from the polished surface of the epitaxial layer as far as the rear side of the substrate wafer is not greater than 60% of the peak density.

### Claim 5 (depends on 1)

A method for producing an epitaxially coated semiconductor wafer, comprising:
providing a substrate wafer comprising monocrystalline silicon, having a front side, a rear side, a center, and a periphery;
depositing an epitaxial layer comprising silicon on the front side of the substrate wafer; treating the epitaxial layer with an oxidant;
treating the epitaxially coated semiconductor wafer with an RTA treatment at a temperature in a temperature range of not less than 1160° C. and not more than 1185° C. for a time period of not less than 15 s and not more than 30 s, wherein the epitaxial layer is exposed to an atmosphere consisting of argon and ammonia and an oxynitride layer forms on the epitaxial layer;
removing the oxynitride layer;
polishing the epitaxial layer; and
recovering an epitaxially coated wafer of claim 1.