Electromagnetic radiation detectors with lattice-matched epitaxial anti-reflection structures
AssigneeApple Inc.
InventorsMatthew T. Morea, Daniel Mahgerefteh, Dylan N. Rees, Mark A. Arbore, Romain F. Chevallier
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Abstract
An electromagnetic radiation detectors includes anti-reflective epitaxial structures incorporated into an epitaxial stack of the electromagnetic radiation detector. An anti-reflective structures as described herein are grown between (and thereby connect) two lattice-matched epitaxial layers that have different refractive indices. The anti-reflective structure reduces Fresnel reflections that would otherwise occur if the two epitaxial layers were directly connected.
Claims20
An electromagnetic radiation detector, comprising:
- an epitaxial stack comprising:
- a first epitaxial layer;
- a second epitaxial layer;
- and
- an anti-reflective epitaxial structure connecting the first epitaxial layer to the second epitaxial layer, wherein:
- the anti-reflective epitaxial structure comprises a plurality of layer groups;
- and
- each layer group of the plurality of layer groups comprises a corresponding plurality of epitaxial layers with a different corresponding average refractive index.
An electromagnetic radiation detector, comprising:
- an epitaxial stack comprising:
- a first epitaxial layer formed from a first semiconductor material;
- a second epitaxial layer formed from a second semiconductor material;
- and
- an anti-reflective epitaxial structure connecting the first epitaxial layer to the second epitaxial layer, wherein:
- the anti-reflective epitaxial structure is formed from a layer of a semiconductor alloy material with varying composition between the first epitaxial layer and the second epitaxial layer;
- and
- the first epitaxial layer, the second epitaxial layer, and the anti-reflective epitaxial structure are lattice matched.
An electromagnetic radiation detector, comprising:
- an epitaxial stack comprising:
- a substrate;
- a first set of buffer layers positioned above the substrate;
- a first electromagnetic radiation absorber layer positioned above the set of buffer layers;
- a cap layer positioned above the electromagnetic radiation absorber layer;
- and
- a first anti-reflective epitaxial structure connecting the first electromagnetic radiation absorber layer to the cap layer.
Dependencies are inferred from the claim text.