US 12,203,191 B2Granted

Method of producing large GaAs and GaP infrared windows

AssigneeBAE Systems Information and Electronic Systems Integration Inc.

InventorsPeter G. Schunemann, Kevin T. Zawilski

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Abstract

A method of growing large GaAs or GaP IR window slabs by HVPE, and in embodiments by LP-HVPE, includes obtaining a plurality of thin, single crystal, epitaxial-quality GaAs or GaP wafers, cleaving the wafers into tiles having ultra-flat, atomically smooth, substantially perpendicular edges, and then butting the tiles together to form an HVPE substrate larger than 4 inches for GaP, and larger than 8 inches or even 12 inches for GaAs. Subsequent HVPE growth causes the individual tiles to fuse by optical bonding into a large “tiled” single crystal wafer, while any defects nucleated at the tile boundaries are healed, causing the tiles to merge with themselves and with the slab with no physical boundaries, and no degradation in optical quality. A dopant such as Si can be added to the epitaxial gases during the final HVPE growth stage to produce EMI shielded GaAs windows.

Claims26

Dependent claims

A slab of GaAs having a largest dimension that is greater than eight inches or a slab of GaP having a largest dimension that is greater than four inches, the slab being suitable for forming an infrared (IR) transparent window, the slab being formed by the process:

obtaining a plurality of epitaxial quality GaAs or GaP wafers;
cleaving the wafers into tiles having cleaved edges;
aligning the cleaved edges of the tiles on a substrate holder in intimate contact, optical bonding thereof thereby yielding a tiled GaAs substrate having a largest dimension that is greater than eight inches or a GaP substrate having a largest dimension that is greater than four inches;
preparing an HVPE reactor having a reaction chamber that is sufficiently large to contain the tiled substrate and to apply gasses thereto;
placing the substrate holder and tiled substrate into the reaction chamber of the HVPE reactor;
applying a plurality of HVPE gases to a surface of the tiled substrate within the reaction chamber, such that at least two of the HVPE gases react with each other to form GaAs or GaP on the tiled substrate via HVPE, thereby causing a slab of GaAs to form on the tiled substrate having a largest dimension of greater than eight inches, or a slab of GaP having a largest dimension of greater than four inches;
and
growing the GaAs or GaP slab via the HVPE to a desired thickness by continuing to apply the gases to a surface of the slab.

5 more elements

A method of producing a slab of GaAs or GaP, the slab being suitable for forming a GaAs infrared (IR) transparent window having a largest dimension that is greater than eight inches, or a GaP infrared (IR) transparent window having a largest dimension that is greater than four inches, the method comprising:

obtaining a plurality of epitaxial quality GaAs or GaP wafers;
cleaving the wafers into tiles having cleaved edges;
aligning the cleaved edges of the tiles on a substrate holder in intimate contact, optical bonding thereof thereby yielding a GaAs tiled substrate having a largest dimension that is greater than eight inches, or a GaP tiled substrate having a largest dimension that is greater than four inches;
preparing an HVPE reactor having a reaction chamber that is sufficiently large to contain the tiled substrate and to apply gasses thereto;
placing the substrate holder and tiled substrate into the reaction chamber of the HVPE reactor;
applying a plurality of HVPE gases to a surface of the tiled substrate within the reaction chamber, such that at least two of the HVPE gases react with each other to form GaAs or GaP on the tiled substrate via HVPE, thereby causing a slab of GaAs to form on the tiled substrate having a largest dimension of greater than eight inches, or a slab of GaP having a largest dimension of greater than four inches;
and
growing the GaAs or GaP slab via the HVPE to a desired thickness by continuing to apply the gases to a surface of the slab.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/073,228Filed 1 Dec 2022
Published: US 2024/0183065 A16 Jun 2024
Granted: 21 Jan 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C30B 25/186
Characterised by the substrate: being specially pre-treated by, e.g. chemical or physical means
C30B 25/20
Characterised by the substrate: the substrate being of the same materials as the epitaxial layer
C30B 29/42
AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi: gallium arsenide
C30B 29/44
AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi: gallium phosphide