Method of fabricating a distributed Bragg reflector by controlling material composition using molecular beam epitaxy
AssigneeThe Regents of the University of California
InventorsEric M. Hall, Guilhem Almuneau
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Abstract
A distributed Bragg reflector for a vertical cavity surface emitting laser has a semiconductor material system including the elements aluminum, gallium, arsenic, and antimony. Accurate control of the composition of the semiconductor material system must be maintained to result in a distributed Bragg reflector suitable for use in a VCSEL. A method of fabricating the distributed Bragg reflector includes calibrating the incorporation of at least one of the elements into the material system as different semiconductor materials are grown on a substrate.
Claims58
A method of controlling material composition in a distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising:
- observing a plurality of reflection high-energy electron diffraction (RHEED) oscillations on a substrate having a multi-layered mirror structure being simultaneously grown on the substrate, wherein the oscillations change when an amount of gallium (Ga) atoms on the substrate exceeds an amount of antimony (Sb) atoms on the substrate;
- measuring a frequency of the plurality of RHEED oscillations, the oscillations indicating the intensity of the movement of the Ga and Sb atoms present on the substrate;
- and
- calibrating the amount of Sb to be incorporated into the substrate depending upon the frequency of the oscillations induced by the Sb atoms and Ga atoms.
A method of controlling material composition of a distributed Bragg reflector, comprising:
- growing epitaxial layers of semiconductor material on a substrate, wherein the layers form a multilayered mirror structure;
- observing a plurality of reflection high-energy electron diffraction (RHEED) oscillations on a surface of the substrate;
- calibrating the incorporation rate of at least one element on the epitaxial layers using frequency measurements from the plurality of RHEED oscillations;
- calibrating the incorporation rate of antimony (Sb) on the epitaxial layers using frequency measurements from the plurality of RHEED oscillations;
- controlling an amount of Ga atoms being applied to the substrate, wherein controlling the amount of Ga atoms includes opening a shutter to allow application of Ga atoms to the substrate and closing the shutter to restrict application of the Ga atoms to the substrate when the frequency of the RHEED oscillations indicates that an excessive number of Ga atoms are being applied to the substrate;
- and
- repeating the steps of calibrating the incorporation rate of Sb atoms, and controlling the amount of Ga atoms until a desired composition of Sb on the substrate is achieved to obtain the multilayered mirror structure.
A method of fabricating a distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising:
- growing epitaxial layers of semiconductor material on a substrate, wherein the layers form a multi-layered mirror structure;
- determining amounts of Sb and Ga to be incorporated into the substrate depending upon a frequency of a plurality of reflection high-energy electron diffraction (RHEED) oscillations induced by Sb atoms and Ga atoms;
- and
- applying the determined amounts of Sb to the substrate to obtain the multi-layered mirror structure.
A method of fabricating a distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising:
- determining an amount of antimony (Sb), in relation to galluim (Ga), to be incorporated into a substrate, the amount of Sb depending upon a frequency of a plurality of reflection high-energy electron diffraction oscillations, wherein the frequency is a measure of movement of atoms of Sb;
- and
- epitaxially growing a multi-layered mirror structure by applying the determined amount of Sb to the multi-layered mirror structure, wherein the multi-layered mirror structure also includes the elements aluminum, gallium, and arsenic.
A method of controlling material composition in a semiconductor structure, the method comprising:
- observing a plurality of reflection high-energy electron diffraction (RHEED) oscillations on a substrate, wherein the oscillations change when an amount of gallium (Ga) atoms on the substrate exceeds an amount of antimony (Sb) atoms on the substrate;
- measuring a frequency of the plurality of RHEED oscillations, the oscillations indicating the intensity of the movement of the Ga and Sb atoms present on the substrate;
- and
- calibrating the amount of Sb to be incorporated into the substrate depending upon the frequency of the oscillations induced by the Sb atoms and Ga atoms.
A method of fabricating a distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising:
- controlling atoms from Group V and Group III elements to be incorporated into a substrate,
- maintaining a ratio of the amount of the atoms between the Group V and Group III elements to be greater than unity for effecting a frequency of RHEED oscillations;
- epitaxially growing a multi-layered mirror
- structure by applying the atoms from Group V and Group III to the multi-layered mirror structure as determined from the frequency of RHEED oscillations;
- and
- wherein the Group V element include at least one of Sb and As, and the Group III element include Ga.
Dependencies are inferred from the claim text.