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AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorsPeter G. Schunemann, Kevin T. Zawilski
Estimating the term…
IR window slabs of GaP greater than 4 inches diameter, and of GaAs greater than 8 inches diameter, are grown on a substrate using Hydride Vapor Phase Epitaxy (HVPE), preferably low pressure HVPE (LP-HVPE). Growth rates can be hundreds of microns per hour, comparable to vertical melt growth. GaAs IR windows produced by the disclosed method exhibit lower absorption than crystals grown from vertical melt near 1 micron, due to reduced impurities and reduced growth temperatures that limit the solubility of excess arsenic, and thereby reduce the “EL2” defects that cause high absorption near one micron in conventional GaAs boules. Silicon wafers can be used as HVPE substrates. For GaAs, layers of GaAsP that vary from 0% to 100% As can be applied to the substrate. EMI shielding can be applied by adding a dopant during the final stage of growth to provide a conductive GaAs or GaP layer.
An infrared window comprising a GaAs slab having a slab largest dimension that is greater than eight inches or a or GaP slab having a slab largest dimension that is greater than four inches, said slab being formed from a substrate wafer of single crystal silicon to which at least one layer of GaAs or GaP has been applied by HVPE, the substrate wafer being subsequently removed from the slab.
A method of producing a slab of GaAs suitable for forming an infrared (IR) transparent window having a window largest dimension that is greater than eight inches or a slab of GaP suitable for forming an infrared (IR) transparent window having a window largest dimension that is greater than eight inches, the method comprising:
Dependencies are inferred from the claim text.