Method for fabricating self-stabilized semiconductor gratings
AssigneeAT&T Bell Laboratories
InventorKeith E. Strege
Life of this patent
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Abstract
A quaternary semiconductor diffraction grating, such as an InGaAsP grating suitable for a DFB laser, is embedded in a semiconductor substrate, such as InP. In one embodiment, the grating is fabricated by (1) forming on the top surface of an InP substrate body an epitaxial layer of InGaAsP coated with an epitaxial layer of InP; (2) forming a pattern of apertures penetrating through the layers of InP and InGaAsP; and (3) heating the body to a temperature sufficient to cause a mass transport of InP from the InP epitaxial layer, the thickness of the InP layer being sufficient to bury the entire surface of the InGaAsP layer with InP.
Claims20
A method of fabricating a semiconductor grating comprising the steps of:
- (a) growing upon a top major surface of a first layer of first semiconductor material a second layer of second semiconductor material;
- (b) growing upon the second layer of second semiconductor material a third layer of third semiconductor material;
- (c) forming a plurality of grooves each of which penetrates through the third layer and through at least a portion of the depth of the second layer;
- the thickness of the third layer being sufficient so that, after the grooves have been formed, the volume of third material in the third layer is greater than the volume of the grooves in the second layer plus the volume of any grooves in the first layer;
- and
- (d) heating the first, second, and third layers to a temperature sufficient to cause a mass transport of the third material of the third layer, whereby the entire surface of the grooves in the second layer and any surface of any grooves in the first layer is substantially buried by the third material.
A method of fabricating a semiconductor grating comprising the steps of
- (a) growing upon a top major surface of a first layer of first semiconductor material a second layer of second semiconductor material;
- (b) growing upon the second layer of second semiconductor material a third layer of third semiconductor material having a thickness greater than the thickness of the second layer;
- (c) forming a plurality of grooves each of which penetrates through the third layer and through at least a portion of the depth of the second layer;
- the thickness of the third layer being sufficient so that, after the grooves have been formed, the volume of third material in the third layer is greater than the volume of the grooves in the second layer;
- and
- (d) hating the first, second, and third layers to a temperature sufficient to cause a mass transport of the third material of the third layer, whereby the substantially entire surface of the second layer is buried with the third material.
Dependencies are inferred from the claim text.