Epitaxial visible-light-emitting devices with light extracted through the substrate and method of making same
AssigneeHE Holdings, Inc.
InventorsAndrew T. Hunter, Jennifer J. Zinck, K. C. Fuller, K. W. Kirby
Life of this patent
Estimating the term…
Abstract
An epitaxial structure suitable for use in a light-emitting device having at least one operating frequency in the visible range, and a method for providing the same. The epitaxial structure includes a semiconductor substrate which is transparent at the operating frequency, an output mirror lattice-matched to the substrate and comprising at least one pair of semiconductor layers having substantially different refractive indices and an active region lattice-matched to the substrate and having a bandgap narrower than the bandgap of the output mirror.
Claims20
An epitaxial system suitable for use in a light-emitting device having at least one operating frequency in the visible range comprising:
- a semiconductor substrate that is transparent at the operating frequency;
- an output mirror comprising at least one pair of adjacent semiconductor layers wherein a first semiconductor layer having a first refractive index and a first wide bandgap, a second semiconductor layer having a second wide bandgap and a second refractive index substantially different from said first refractive index;
- an active region comprising at least one active layer, said active layer having a bandgap narrower than the first wide bandgap and the second wide bandgap;
- wherein said active region and said output mirror are substantially lattice matched to said substrate.
A semiconductor target suitable for a device emitting a light beam having an optical wavelength within the visible range consisting essentially of:
- a semiconductor substrate that is transparent at the optical wavelength;
- an output mirror comprising at least one pair of adjacent semiconductor layers wherein a first semiconductor layer having a first refractive index and a first wide bandgap, a second semiconductor layer having a second wide bandgap and a second refractive index substantially different from said first refractive index;
- an active region comprising at least one active layer, said active layer having a bandgap narrower than the first wide bandgap and the second wide bandgap;
- an input mirror;
- wherein said active region and said output mirror are substantially lattice matched to said substrate.
A method for making an epitaxial system suitable for use in a device for emitting at least one light beam having an optical wavelength within the visible range, the steps comprising:
- providing a semiconductor substrate that is transparent at the optical wavelength;
- providing an output mirror over said substrate, said output mirror comprising at least one pair of adjacent semiconductor layers wherein a first semiconductor layer having a first refractive index and a first wide bandgap, a second semiconductor layer having a second wide bandgap and a second refractive index substantially different from said first refractive index;
- providing an active region including at least one active layers over said output mirror, said active layer having a bandgap narrower than the first wide bandgap and the second wide bandgap;
- wherein said active region and said output mirror are substantially lattice matched to said substrate.
A method for making a semiconductor target suitable for a device for emitting at least one light beam having an optical wavelength within the visible range, the steps comprising:
- providing a semiconductor substrate which is transparent at the optical wavelength, said substrate including MF.sub.2, where M is selected from the group consisting of strontium, lead, barium and calcium;
- annealing said substrate in a reactive HF/He atmosphere at a final anneal temperature that is greater than about 300.degree. and less than about 1400.degree. C. or the melting point of the substrate, whichever is less;
- providing an output mirror over said substrate, said output mirror comprising at least one pair of adjacent semiconductor layers wherein a first semiconductor layer having a first refractive index and a first wide bandgap, a second semiconductor layer having a second wide bandgap and a second refractive index substantially different from said first refractive index;
- providing an active region including at least one active layers over said output mirror, said active layer having a bandgap narrower than the first wide bandgap and the second wide bandgap;
- wherein said active region and said output mirror are substantially lattice matched to said substrate.
A method for reducing roughness of a semiconductor substrate surface, comprising the steps of:
- providing a substrate including MF.sub.2, where M is selected from the group consisting of strontium, lead, barium and calcium;
- annealing said substrate in a reactive HF/He atmosphere at a final anneal temperature that is greater than about 300.degree. and less than about 1400.degree. C. or the melting point of the substrate, whichever is less.
Dependencies are inferred from the claim text.