# US 7,608,524 B2 · Method of and system for forming SiC crystals having spatially uniform doping impurities

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- Number: US 7,608,524 B2
- Document ID: US7608524B2
- Status: Granted
- Kind: B2
- Application number: 11/405,368
- Filed: 2006-04-17
- Published: 2006-11-02
- Granted: 2009-10-27
- Earliest claimed: 2005-04-19
- Assignees: II-VI Incorporated
- Inventors: Avinash K. Gupta; Edward Semenas; Ilya Zwieback; Donovan L. Barrett; Andrew E. Souzis
- Web page: https://patentgrep.com/patent/US7608524B2

## CPC

- C30B 29/36: Carbides
- C30B 23/00: Single-crystal growth by condensing evaporated or sublimed materials
- Y10T 117/10: Apparatus
- Y10T 117/1008: with responsive control means
- Y10T 117/1016: with means for treating single-crystal [e.g., heat treating]
- Y10T 117/108: Including a solid member other than seed or product contacting the liquid [e.g., crucible, immersed heating element]
- 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
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

In a physical vapor transport method and system, a growth chamber charged with source material and a seed crystal in spaced relation is provided. At least one capsule having at least one capillary extending between an interior thereof and an exterior thereof, wherein the interior of the capsule is charged with a dopant, is also provided. Each capsule is installed in the growth chamber. Through a growth reaction carried out in the growth chamber following installation of each capsule therein, a crystal is formed on the seed crystal using the source material, wherein the formed crystal is doped with the dopant.

## Claims

### Claim 1

A physical vapor transport method comprising:
(a) providing a growth chamber charged with source material and a seed crystal in spaced relation;
(b) providing at least one capsule having an interior that is charged with dopant, wherein each capsule is comprised of a porous material having pores therein and each capsule includes, in addition to the pores of the porous material, at least one calibrated capillary of predetermined dimensions extending between the interior of the capsule and an exterior of the capsule;
(c) installing each capsule in the growth chamber; and
(d) through a growth reaction carried out in the growth chamber following step (c), forming a crystal on the seed crystal using the source material, wherein the formed crystal is doped with the dopant via controlled effusion of the dopant through the at least one capillary in each capsule.

### Claim 2 (depends on 1)

The method of claim 1, wherein at least one of the growth chamber and the capsule is made of a material that is not reactive with the source material or the dopant.

### Claim 3 (depends on 2)

The method of claim 2, wherein the material forming the growth chamber and/or the capsule is graphite.

### Claim 4 (depends on 1)

The method of claim 1, wherein the dopant:
is in one of the following chemical forms: elemental; carbide and silicide; and/or has at least one of the following physical forms: powder, pieces and/or chips.

### Claim 5 (depends on 1)

The method of claim 1, wherein:
the dopant includes at least one of the following: vanadium, aluminum, boron and phosphorus.

### Claim 6 (depends on 1)

The method of claim 1, wherein, prior to step (d), the source material is initially in powder form.

### Claim 7 (depends on 1)

The method of claim 1, wherein the source material includes SiC.

### Claim 8 (depends on 1)

The method of claim 1, wherein step (d) includes:
evacuating the growth chamber; and
heating the growth chamber to a desired reaction temperature such that a temperature gradient is created between the source material and the seed crystal whereupon the seed crystal is at a lower temperature than the source material.

### Claim 9 (depends on 1)

The method of claim 1, wherein, prior to heating the growth chamber, step (d) includes filling the growth chamber with inert gas to a desired pressure.