Method to reduce crystal defects particularly in group III-nitride layers and substrates
OwnerAndreas A. Melasinventor
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Abstract
Gallium Nitride layers grown as single crystals by epitaxy such as Hydride Vapor Phase Epitaxy (HVPE) contain large numbers of crystal defects such as hexagonal pits, which limit the yield and performance of opto- and electronic devices. In this method, the Gallium Nitride layer is first coated with an Aluminum layer of approximate thickness of 0.1 microns. Next, Nitrogen is ion implanted through the Aluminum layer so as to occupy mostly the top 0.1 to 0.5 microns of the Gallium Nitride layer. Finally, through a pulsed directed energy beam such as electron or photons, with a fluence of approximately 1 Joule/cm2 the top approximately 0.5 microns are converted to a single crystal with reduced defect density.
Claims14
A method of improving the crystal quality of a Group III Nitride compound semiconductor layer epitaxially grown on a lattice mismatched substrate comprising:
- A. providing said Group III Nitride compound semiconductor epitaxial layer and said Group III Nitride compound semiconductor epitaxial layer comprises a top surface;
- B. placing said layer of said Group III Nitride compound semiconductor material into an electron beam metal deposition tool and depositing a layer of Group III metal component upon said top surface;
- C. placing said layer of said Group III Nitride compound semiconductor with said deposited layer of said Group III metal component into an ion implantation tool and implanting a Nitrogen component through said Group metal component layer into said Group III Nitride compound semiconductor epitaxial layer, thereby forming a Group III Nitride compound semiconductor layer with an excess of unreacted nitrogen;
- D. placing said layer of said Group III Nitride compound semiconductor with said deposited Group III metal layer and said implanted Nitrogen component into a directed pulsed electron beam tool and exposing said layers to a pulsed electron beam;
- wherein said Group III Nitride compound semiconductor layer after exposure to said pulsed electron beam exhibits a reduction of hexagonal pits, an increase in x ray diffraction height and an increase in the crystallite size compared to the as deposited Group III Nitride compound semiconductor layer.
Dependencies are inferred from the claim text.