# US 5,347,157 A · Multilayer structure having a (111)-oriented buffer layer

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- Number: US 5,347,157 A
- Document ID: US5347157A
- Status: Granted
- Kind: A
- Application number: 07/992,213
- Filed: 1992-12-17
- Granted: 1994-09-13
- Earliest claimed: 1992-12-17
- Assignees: Eastman Kodak Company
- Inventors: Liang-Sun Hung; John A. Agostinelli; Jose M. Mir
- Web page: https://patentgrep.com/patent/US5347157A

## CPC

- G02F 1/37: for second-harmonic generation {(G02F1/3532 takes precedence)}
- C30B 23/02: Epitaxial-layer growth
- C30B 29/68: Crystals with laminate structure, e.g. "superlattices"
- G02B 6/131: {by using epitaxial growth (epitaxial growth for semiconductors H10P14/20)}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- 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
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A multilayer structure comprising in order: a (111)-oriented single crystal substrate and an epitaxial metal oxide buffer layer. The substrate is doped or undoped. The substrate is a semiconductor selected from the group consisting of Si compounds, Ge compounds, and compounds having at least one element selected from the group consisting of Al, Ga, and In and at least one element selected from the group consisting of N, P, As, and Sb. The substrate defines a substrate superlattice dimension equal to 3 times a sublattice constant of the substrate. The epitaxial metal oxide buffer layer has a three-fold rotation symmetry about the substrate (111) direction. The buffer layer defines a buffer layer superlattice dimension equal to 4 times the oxygen-to-oxygen lattice spacing of the buffer layer. The buffer layer superlattice dimension is within 15 percent of the substrate superlattice dimension.

## Claims

### Claim 1

A multilayer structure comprising in order:
a (111)-oriented single crystal substrate, said substrate being doped or undoped, said substrate being a semiconductor selected from the group consisting of Si.sub.x Ge.sub.1-x semiconductors, wherein x is from 0 to 1, and semiconductors having at least one element selected from the group consisting of Al, Ca, and In and at least one element selected from the group consisting of N, P, As, and Sb, said substrate defining a substrate superlattice dimension equal to 3 times a sublattice constant of said substrate; and
an epitaxial metal oxide buffer layer having a three-fold rotation symmetry about the substrate <111>direction, said buffer layer defining a buffer layer superlattice dimension equal to 4 times the oxygen-to-oxygen lattice spacing of said buffer layer, said buffer layer superlattice dimension being within 15 percent of said substrate superlattice dimension.

### Claim 2 (depends on 1)

The multilayer structure of claim 1 further comprising an epitaxial metal oxide film deposited on said buffer layer.

### Claim 3 (depends on 1)

The multilayer structure of claim 1 wherein said buffer layer is selected from the group consisting of (111)MgO, (0001)Al.sub.2 O.sub.3, (0001)Ga.sub.2 O.sub.3, and (111)SrTiO.sub.3.

### Claim 4 (depends on 3)

The multilayer structure of claim 3 further comprising an epitaxial film of (0001)LiNb.sub.x Ta.sub.1-x O.sub.3, wherein x is from 0 to 1, deposited on said buffer layer.

### Claim 5 (depends on 4)

The multilayer structure of claim 4 wherein said substrate is selected from the group consisting of GaP, InP, InAs, GaSb, Al.sub.x Ga.sub.1-x As, and Si.sub.x Ge.sub.1-x, wherein x is from 0 to 1.

### Claim 6 (depends on 1)

The multilayer structure of claim 1 wherein said buffer layer is (111)MgO.

### Claim 7 (depends on 6)

The multilayer structure of claim 6 further comprising a nonlinear optical film deposited on said buffer layer.

### Claim 8 (depends on 6)

The multilayer structure of claim 6 further comprising an epitaxial film of (0001)LiNb.sub.x Ta.sub.1-x O.sub.3, wherein x is from 0 to 1, deposited on said buffer layer.

### Claim 9 (depends on 6)

The multilayer structure of claim 6 wherein said substrate is Al.sub.x Ga.sub.1-x As, wherein x is from 0 to 1.

### Claim 10

A multilayer structure comprising in order: a (111)-oriented single crystal semiconductor substrate, said substrate being doped or undoped and being selected from the group consisting of GaP, InP, InAs, GaSb, Al.sub.x Ga.sub.1-x As, and Si.sub.x Ge.sub.1-x, wherein x is from 0 to 1; and an epitaxial metal oxide buffer layer selected from the group consisting of (111)MgO, (0001)Al.sub.2 O.sub.3, (0001)Ga.sub.2 O.sub.3, and (111)SrTiO.sub.3, said substrate defining a substrate superlattice dimension equal to 3 times a sublattice constant of said substrate, said buffer layer defining a buffer layer superlattice dimension equal to 4 times the oxygen-to-oxygen lattice spacing of said buffer layer, said buffer layer superlattice dimension being within 10 percent of said substrate superlattice dimension.

### Claim 11 (depends on 10)

The multilayer structure of claim 10 wherein said substrate is Al.sub.x Ga.sub.1-x As, wherein x is from 0 to 1.

### Claim 12 (depends on 10)

The multilayer structure of claim 10 further comprising an epitaxial film of (0001)LiNb.sub.x Ta.sub.1-x O.sub.3, wherein x is from 0 to 1, deposited on said buffer layer.

### Claim 13 (depends on 12)

The multilayer structure of claim 12 wherein said substrate is GaAs.

### Claim 14

A multilayer structure comprising in order: a (111)-oriented single crystal semiconductor substrate, said substrate being doped or undoped and being selected from the group consisting of GaP, InP, InAs, GaSb, Al.sub.x Ga.sub.1-x As, and Si.sub.x Ge.sub.1-x, wherein x is from 0 to 1; and an epitaxial (111)MgO buffer layer.

### Claim 15 (depends on 14)

The multilayer structure of claim 14 further comprising a nonlinear optical film deposited on said buffer layer.

### Claim 16 (depends on 14)

The multilayer structure of claim 14 further comprising an epitaxial film of (0001)LiNb.sub.x Ta.sub.1-x O.sub.3, wherein x is from 0 to 1, deposited on said buffer layer.

### Claim 17 (depends on 16)

The multilayer structure of claim 16 wherein said substrate is Al.sub.x Ga.sub.1-x As, wherein x is from 0 to 1.

### Claim 18 (depends on 16)

The multilayer structure of claim 16 wherein said substrate is GaAs.

### Claim 19 (depends on 14)

The multilayer structure of claim 14 wherein said substrate is Al.sub.x Ga.sub.1-x As, wherein x is from 0 to 1.