Method of fabricating optical device using multiple sacrificial spacer layers

Abstract

The present invention is a method of fabricating an optical device using multiple sacrificial spacer layers. The first step in this process is to fabricate the underlying base structure and deposit an optical structure thereon. A facet is then created at the ends of the optical structure and alternating sacrificial and intermediate layers are fabricated on the device. A mask layer is deposited on the structure, with openings created in the layers to allow use of an etchant. User-defined portions of the spacer layers are subsequently removed with the etchant to create air gaps between the intermediate layers.

What is claimed is: 
     
       1. A method for creating a photonic device comprising the steps of:
 a) selecting a base structure; 
 b) forming an optical structure on the base structure; 
 c) forming a coherent photonic emitter device on the optical structure; 
 d) depositing at least one metal contact on the coherent photonic emitter device; 
 e) creating at least one facet having a first surface on the coherent photonic emitter structure device, the optical structure, and the base structure, wherein the facet and an output trench are created simultaneously by etching at least one trench and facet into the base structure; 
 f) depositing a first sacrificial spacer layer along the horizontal and vertical trench surfaces and a user-definable portion of the optical structure; 
 g) depositing an intermediate layer on the sacrificial spacer layer; 
 h) returning to steps (f) and (g)repeating said depositing a first sacrificial layer and said depositing an intermediate layer if additional sacrificial spacer layers are desired, otherwise proceeding to step (i); 
 i) depositing a mask layer over the sacrificial spacer layers and the intermediate layers deposited in steps (f), (g) and (h); 
 j) defining openings in the mask layer beside the facets adjacent to each end of a trench; 
 k) etching holes in the sacrificial spacer and the intermediate layers beneath the openings in the mask layer; and 
 l) removing a user-definable portion of each sacrificial spacer layer. 
 
     
     
       2. The method of  claim 1 , further including the step of comprising removing a user-definable portion of the mask layer. 
     
     
       3. The method of  claim 2 , wherein the step of creating at least one facet having a first surface on the coherent photonic emitter structure, optical structure and base structure, wherein the facet and an output trench are created simultaneously by etching at least one trench and facet into the base structure further comprises creating at least one facet having a first surface on the coherent photonic emitter structure, optical structure and base structure, wherein the facet and an output trench are created simultaneously by etching at least one trench and facet into the base structure, and further wherein the at least one metal contact acts as an etch mask for the facets of the photonic emitter structure device during said creating at least one facet having a first surface on the coherent photonic emitter device, the optical structure, and the base structure. 
     
     
       4. The method of  claim 3 , wherein the step of said creating at least one facet having a first surface on the coherent photonic emitter structure device, the optical structure, and the base structure, wherein the facet and an output trench are created simultaneously by etching at least one trench and facet into the base structure, and further wherein the at least one metal contact acts as an etch mask for the facets of photonic emitter structure further comprises the steps of:
 a) patterning a photoresist on the photonic device such that it defines openings at the edges of the optical structure where a trench is formed, wherein the openings overlapping overlap with the edges of the metal contact where the facets will be formed such that the metal contact is exposed to the etch along its respective edges; and 
 b) etching the photonic device through the photoresist to create the at least one facet and trench, wherein the mask layer acts as an etch mask to protect the photonic device. 
 
     
     
       5. The method of step claim  4 , wherein the mask layer is a photoresist. 
     
     
       6. The method of step claim  5 , wherein the optical photonic device is a semiconductor laser. 
     
     
       7. A method for creating a photonic device, the method comprising:
 forming a coherent photonic emitter device on an optical structure;   creating a facet relative to the optical structure, wherein the facet and an output trench are created simultaneously by etching a trench and facet into a base structure;   depositing a sacrificial spacer layer along horizontal and vertical surfaces of the trench and a user-definable portion of the optical structure;   depositing an intermediate layer on the sacrificial spacer layer;   depositing a mask layer over the sacrificial spacer layer and the intermediate layer;   forming one or more openings in the mask layer beside the facet adjacent to each end of the trench;   forming holes in the sacrificial spacer layer and the intermediate layer beneath the one or more openings in the mask layer; and   removing a user-definable portion of the sacrificial spacer layer to form a gap between the facet and the intermediate layer.   
     
     
       8. The method of claim 7, further comprising:
 selecting a base structure; and   forming the optical structure on the base structure.   
     
     
       9. The method of claim 7, further comprising depositing a metal contact on the coherent photonic emitter device. 
     
     
       10. The method of claim 9, wherein said creating a facet relative to the optical structure comprises creating a facet having a surface on the coherent photonic emitter device and the optical structure, and wherein the metal contact acts as an etch mask for the facet of the photonic emitter structure during said creating a facet relative to the optical structure. 
     
     
       11. The method of claim 10, wherein said creating a facet relative to the optical structure further comprises:
 patterning a photoresist on the photonic device to define openings at edges of the optical structure where a trench is formed, wherein the openings overlap with edges of the metal contact where the facets will be formed such that the metal contact is exposed to the etch along its respective edges; and   etching the photonic device through the photoresist to create the facet and trench, wherein the mask layer acts as an etch mask to protect the photonic device.   
     
     
       12. The method of claim 11, wherein the mask layer is a photoresist. 
     
     
       13. The method of claim 7, further comprising repeating said depositing a sacrificial spacer layer and said depositing an intermediate layer to form additional sacrificial spacer layers. 
     
     
       14. The method of claim 7, wherein said depositing a sacrificial spacer layer comprises depositing a sacrificial spacer layer for a dimensional purpose and for no optical characteristic of the sacrificial spacer layer. 
     
     
       15. The method of claim 7, further comprising removing a user-definable portion of the mask layer. 
     
     
       16. The method of claim 7, wherein the photonic device is a semiconductor laser. 
     
     
       17. A method for creating a photonic device, the method comprising:
 forming a coherent photonic emitter device on an optical structure;   creating a facet relative to the optical structure, wherein the facet and an output trench are created simultaneously by etching a trench and facet into a base structure;   depositing a sacrificial spacer layer along horizontal and vertical surfaces of the trench and a user-definable portion of the optical structure;   depositing an intermediate layer on the sacrificial spacer layer;   depositing a mask layer over the sacrificial spacer layer and the intermediate layer;   forming one or more openings in the mask layer beside the facet adjacent to each end of the trench;   forming holes in the sacrificial spacer layer and the intermediate layer beneath the one or more openings in the mask layer; and   fabricating a waveguide on the sacrificial spacer layer and the intermediate layer, wherein the waveguide fills a user-definable portion of the trench.   
     
     
       18. An apparatus comprising:
 a coherent photonic emitter device formed on an optical structure;   a facet and an output trench formed relative to the optical structure;   a sacrificial spacer layer formed along horizontal and vertical surfaces of the output trench;   an intermediate layer formed on the sacrificial spacer layer;   a mask layer formed on the sacrificial spacer layer and the intermediate layer;   one or more openings formed in the mask layer, the sacrificial spacer layer, and the intermediate layer; and   a waveguide located on the sacrificial spacer layer and the intermediate layer, wherein the waveguide fills a user-definable portion of the output trench.   
     
     
       19. The apparatus of claim 18, further comprising a metal contact located on the coherent photonic emitter device. 
     
     
       20. The apparatus of claim 19, wherein the photonic device is a semiconductor laser.