Oxide spacer HCG VCSELS and fabrication methods
AssigneeThe Regents of the University of California
InventorsConstance J. Chang-Hasnain, Kevin T. Cook, Jipeng Qi, Jiaxing Wang
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Abstract
A high-contrast grating (HCG) structure and method of fabrication. The grating of the HCG is formed over a structural spacer layer, allowing a wider range of grating patterns, such as post and other forms which are lack structural support when fabricated over an air spacing beneath the grating elements. The technique involves etching the HCG grating, followed by oxidizing through this HCG grating into an oxide spacer layer beneath it creating a low-index area beneath the grating. This form of HCG reflector can be utilizes as upper and/or lower reflectors in fabricating vertical cavity surface emitting lasers (VCSELs).
Claims26
An oxide-spacer high-contrast grating (HCG) reflector apparatus formed as part of an epitaxial structure, comprising:
- (a) a grating of high-refractive index semiconductor formed from patterning a high contrast grating (HCG) layer disposed over an oxidizable spacer layer;
- (b) an area of low-refractive index oxide formed locally within said oxidizable spacer layer beneath the grating, with the combination forming a HCG reflector apparatus;
- and
- (c) wherein said low-refractive index oxide is formed locally within said oxidizable spacer layer by performing oxidation of the oxidizable spacer layer through the grating of the HCG layer, and wherein the material of said HCG layer is selected to retain a high refractive index through this oxidation process.
A vertical-cavity surface-emitting laser (VCSEL) apparatus, comprising:
- (a) a lower reflector and an upper reflector;
- and
- (b) a gain region disposed between said lower and upper reflectors;
- (c) wherein said upper reflector and/or said lower reflector comprise an oxide spacer high-contrast grating (HCG) reflector formed as part of an epitaxial structure, comprising:
- (i) a grating of high-refractive index semiconductor formed from patterning a high contrast grating (HCG) layer disposed over an oxidizable spacer layer;
- (ii) an area of low-refractive index oxide formed locally within said oxidizable spacer layer beneath the grating, with the combination forming a HCG reflector apparatus;
- and
- (iii) wherein said low-refractive index oxide is formed locally within said oxidizable spacer layer by performing oxidation of the oxidizable spacer layer through the grating of the HCG layer, and wherein the material of said HCG layer is selected to retain a high refractive index through this oxidation process.
Dependencies are inferred from the claim text.