Hybrid ridge waveguide

Abstract

Embodiments of the invention relate to an electro-optic device comprising a first region of silicon semiconductor material and a second region of III-V semiconductor material. A waveguide of the optical device is formed in part by a ridge in the second region. An optical mode of the waveguide is laterally confined by the ridge of the second region and vertically confined by a vertical boundary included in the first region. The ridge structure further serves as a current confinement structure over the active region of the electro-optic device, eliminating the need for implantation or other structures that are known to present reliability problems during manufacturing. The lack of “voids” and implants in electro-optic devices according to embodiments of the invention leads to better device reliability, process repeatability and improved mechanical strength.

1 . An apparatus comprising:
 a first semiconductor slab comprising a silicon material and including a first vertical boundary;   a second semiconductor slab above the first semiconductor slab comprising a III-V material and including a ridge;   at least one overclad region coupled to the ridge of the second semiconductor slab; and   an optical waveguide included in the first and second semiconductor slab and formed, at least in part, by the ridge, the first vertical boundary and the overclad region(s) to vertically confine an optical mode of the optical waveguide, the ridge to laterally confine the optical mode.   
     
     
         2 . The apparatus of  claim 1 , further comprising
 an n-type electrical contact coupled to the second semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   wherein the second semiconductor slab further comprises:   a p-type layer including the ridge and coupled to the p-type electrical contact;   an n-type layer coupled to the first semiconductor slab and the n-type electrical contact; and   an active layer disposed between the n-type layer and the p-type layer.   
     
     
         3 . The apparatus of  claim 1 , further comprising
 an n-type electrical contact coupled to the second semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   
       wherein the second semiconductor slab further comprises:
 an n-type layer including the ridge and coupled to the n-type electrical contact; 
 a p-type layer coupled to the first semiconductor slab and the p-type electrical contact; and 
 an active layer disposed between the p-type layer and the n-type layer. 
 
     
     
         4 . The apparatus of  claim 1 , wherein the second semiconductor slab further comprises:
 a first n-type layer including the ridge;   a second n-type layer coupled to the first semiconductor slab; and   an active layer disposed between the first and second n-type layers, the active layer including a tunnel junction to convert n-type majority carriers of one of the n-type layers to p-type majority carriers.   
     
     
         5 . The apparatus of  claim 1 , further comprising
 an n-type electrical contact coupled to the first semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   wherein the first and second semiconductor slabs are coupled via a conductive bonding layer, and the second semiconductor slab further comprises:   a p-type layer including the ridge and coupled to the p-type electrical contact;   an n-type layer coupled to the conductive bonding layer, and   an active layer disposed between the n-type layer and the p-type layer.   
     
     
         6 . The apparatus of  claim 1 , further comprising a silicon substrate layer below the first semiconductor slab, wherein the first vertical boundary comprises a first vertical confinement layer disposed between the first semiconductor slab and the silicon substrate layer. 
     
     
         7 . The apparatus of  claim 6 , wherein the first vertical confinement layer comprises a material with a lower refractive index than silicon. 
     
     
         8 . The apparatus of  claim 2 , the ridge further included in the active layer and to extend to the n-type layer. 
     
     
         9 . The apparatus of  claim 5 , the ridge further included in the active layer and the n-type layer and to extend to the conductive bonding layer. 
     
     
         10 . A system comprising:
 a light source;   a modulator to receive light from the light source; and   a transmission medium to operatively couple the light source and the modulator; wherein at least one of the light source and the modulator includes an optical device comprising
 a first semiconductor slab comprising a silicon material and including a first vertical boundary, 
 a second semiconductor slab above the first semiconductor slab comprising a III-V material and including a ridge, and 
 an optical waveguide included in the first and second semiconductor slab and formed, at least in part, by the ridge, the first vertical boundary to vertically confine an optical mode of the optical waveguide, the ridge to laterally confine the optical mode. 
   
     
     
         11 . The system of  claim 10 , the optical device further comprising
 an n-type electrical contact coupled to the second semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   wherein the second semiconductor slab further comprises:   a p-type layer including the ridge and coupled to the p-type electrical contact;   an n-type layer coupled to the first semiconductor slab and the n-type electrical contact; and   an active layer disposed between the n-type layer and the p-type layer.   
     
     
         12 . The system of  claim 10 , the optical device further comprising
 an n-type electrical contact coupled to the second semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   
       wherein the second semiconductor slab further comprises:
 an n-type layer including the ridge and coupled to the n-type electrical contact; 
 a p-type layer coupled to the first semiconductor slab and the p-type electrical contact; and 
 an active layer disposed between the p-type layer and the n-type layer. 
 
     
     
         13 . The system of  claim 10 , wherein the second semiconductor slab of the optical device further comprises:
 a first n-type layer including the ridge;   a second n-type layer coupled to the first semiconductor slab; and   an active layer disposed between the first and second n-type layers, the active layer including a tunnel junction to convert n-type majority carriers of one of the n-type layers to p-type majority carriers.   
     
     
         14 . The system of  claim 10 , the optical device further comprising
 an n-type electrical contact coupled to the first semiconductor slab; and   a p-type electrical contact coupled to the second semiconductor slab;   
       wherein the first and second semiconductor slabs are coupled via a conductive bonding layer, and the second semiconductor slab further comprises:
 a p-type layer including the ridge and coupled to the p-type electrical contact; 
 an n-type layer coupled to the conductive bonding layer, and 
 an active layer disposed between the n-type layer and the p-type layer. 
 
     
     
         15 . The system of  claim 10 , the optical device further comprising a silicon substrate layer below the first semiconductor slab, wherein the first vertical boundary comprises a first vertical confinement layer disposed between the first semiconductor slab and the silicon substrate layer. 
     
     
         16 . The system of  claim 15 , wherein the first vertical confinement layer comprises a material with a lower refractive index than silicon. 
     
     
         17 . The system of  claim 12 , the ridge of the optical device further included in the active layer and to extend to the n-type layer. 
     
     
         18 . The system of  claim 14 , the ridge of the optical device further included in the active layer and the n-type layer and to extend to the conductive bonding layer.