Method for accurate growth of vertical-cavity surface-emitting lasers
AssigneeSandia Corporation
InventorsScott A. Chalmers, Kevin P. Killeen, Kevin L. Lear
Life of this patent
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Abstract
We report a method for accurate growth of vertical-cavity surface-emitting lasers (VCSELs). The method uses a single reflectivity spectrum measurement to determine the structure of the partially completed VCSEL at a critical point of growth. This information, along with the extracted growth rates, allows imprecisions in growth parameters to be compensated for during growth of the remaining structure, which can then be completed with very accurate critical dimensions. Using this method, we can now routinely grow lasing VCSELs with Fabry-Perot cavity resonance wavelengths controlled to within 0.5%.
Claims19
A method of producing a vertical-cavity surface-emitting laser (VCSEL) structure having a bottom mirror means, a central optical cavity, and a top mirror means, in which the VCSEL is to have a design Fabry-Perot cavity resonance wavelength, the method comprising:
- forming a first set of distributed Bragg reflector (DBR) layers to form the bottom mirror means,
- forming from about 94% to less than 100% of the central optical cavity,
- measuring the reflectivity spectra of the combined bottom mirror means and the partially formed central cavity,
- determining the correct thickness for the remaining portion of the central optical cavity from the measured reflectivity spectra that is necessary to achieve the design cavity resonance wavelength for the completed central optical cavity, and
- forming the remainder of the central optical cavity at the correct thickness and then forming a second set of distributed Bragg reflector (DBR) layers to form the top mirror means.
A method of producing a vertical-cavity surface-emitting laser (VCSEL) structure having a bottom mirror means, a central optical cavity, and a top mirror means, in which the VCSEL is to have a design Fabry-Perot cavity resonance wavelength, the method comprising:
- forming a first set of distributed Bragg reflector (DBR) layers to form the bottom mirror means,
- forming from about 94% to less than 100% of the central optical cavity,
- measuring the reflectivity spectra of the combined bottom mirror means and the partially formed central cavity to determine the bottom mirror means center wavelength and the resonance wavelength of the partially formed central cavity,
- determining the correct thickness for the remaining portion of the central optical cavity that is necessary to achieve the design cavity resonance wavelength for the completed central optical cavity,
- determining the correct thickness of the top mirror means to compensate for inaccuracy in the thickness of the bottom mirror means,
- forming the remainder of the central optical cavity at the correct thickness, and then
- forming a second set of distributed Bragg reflector (DBR) layers to form the top mirror means at the correct thickness.
A method of producing a vertical-cavity surface-emitting laser (VCSEL) structure having a bottom mirror means, a central optical cavity, and a top mirror means, in which the VCSEL is to have a design Fabry-Perot cavity resonance wavelength, the method comprising:
- forming a first set of distributed Bragg reflector (DBR) layers to form the bottom mirror means,
- growing the central optical cavity, while measuring the reflectivity spectra of the combined bottom mirror means and the central optical cavity to determine the resonance wavelength of the central optical cavity as growth proceeds;
- stopping growth of the central optical cavity when said resonance wavelength is equal to, within an acceptable tolerance, the design Fabry-Perot cavity resonance wavelength;
- and
- forming a second set of distributed Bragg reflector (DBR) layers to form the top mirror means.
Dependencies are inferred from the claim text.