Method and system for heterogeneous substrate bonding for photonic integration
A method of fabricating a composite integrated optical device includes providing a substrate comprising a silicon layer, forming a waveguide in the silicon layer, and forming a layer comprising a metal material coupled to the silicon layer. The method also includes providing an optical detector, forming a metal-assisted bond between the metal material and a first portion of the optical detector, forming a direct semiconductor-semiconductor bond between the waveguide, and a second portion of the optical detector.
1. A hybrid integrated optical device comprising:
a substrate comprising a silicon layer;
a first pad, disposed on a first region of the silicon layer and bonded to the silicon layer;
a compound semiconductor device;
a second pad, disposed on a first region of the compound semiconductor device and bonded to the compound semiconductor device; and
a bonding metal, wherein:
the bonding metal comprises In 0.7 Pd 0.3 ;
the bonding metal is disposed between the first pad and the second pad;
the bonding metal is bonded to the first pad and the second pad; and
the bonding metal, the first pad, and the second pad secure the compound semiconductor device to the silicon layer of the substrate;
and wherein:
the substrate and the compound semiconductor bond to form a second bond between a second region of the silicon layer and a second region of the compound semiconductor device, and the second bond is one of:
a direct semiconductor/semiconductor bond, or
a metal-assisted semiconductor/semiconductor bond that includes a metal interface layer having a thickness of less than 100 Å, wherein the metal interface layer is between the second region of the silicon layer and the second region of the compound semiconductor device.
2. The hybrid integrated optical device of claim 1 , wherein the bonding metal is In 0.7 Pd 0.3 .
3. The hybrid integrated optical device of claim 1 , wherein:
the first pad comprises at least one of Ti, Cr, Pt, Ni or W; and
the second pad comprises at least one of Ti, Cr, Pt, Ni or W.
4. The hybrid integrated optical device of claim 1 , wherein the substrate is a silicon-on-insulator substrate comprising a silicon handle portion, an oxide layer, and the silicon layer.
5. The hybrid integrated optical device of claim 1 , wherein:
the second bond is the metal-assisted semiconductor/semiconductor bond;
the silicon layer includes a third region;
the compound semiconductor device includes a third region; and
the third region of the silicon layer and the third region of the compound semiconductor device are bonded by a direct semiconductor/semiconductor bond.
6. The hybrid integrated optical device of claim 5 , further comprising a light-emitting device that is operable to emit light through the direct semiconductor/semiconductor bond.
7. The hybrid integrated optical device of claim 6 , wherein the light-emitting device is a III-V optical device.
8. The hybrid integrated optical device of claim 6 , wherein the light-emitting device is an optical generator.
9. The hybrid integrated optical device of claim 5 , wherein light propagates parallel to an interface between the third region of the silicon layer and the third region of the compound semiconductor device, such that the light evanescently couples across the direct semiconductor/semiconductor bond, between the silicon layer and the compound semiconductor device.
10. The hybrid integrated optical device of claim 1 , wherein a first portion of the silicon layer forms a recess proximate the first pad, and wherein a top surface of the compound semiconductor device is coplanar with a second portion of the silicon layer.
11. The hybrid integrated optical device of claim 1 , further comprising a planarizing material.
12. The hybrid integrated optical device of claim 11 , wherein at least a portion of the planarizing material is removed, and further comprising an interconnect metal that provides electrical connectivity to at least one of the compound semiconductor device and the silicon layer, at a location where the portion of the planarizing material is removed.
13. A hybrid integrated optical device comprising:
a first semiconductor comprising a first optical element;
a first pad, disposed on a first region of the first semiconductor and bonded to the first semiconductor;
a second semiconductor comprising a second optical element;
a second pad, disposed on a first region of the second semiconductor and bonded to the second semiconductor; and
a bonding metal, wherein:
the bonding metal is In 0.7 Pd 0.3 ;
the bonding metal is disposed between the first pad and the second pad;
the bonding metal is bonded to the first pad and the second pad; and
the bonding metal, the first pad, and the second pad secure the first semiconductor to the second semiconductor; and
the first optical element is directly optically coupled with the second optical element;
and wherein:
the first semiconductor and the second semiconductor bond to form a second bond between a second region of the first semiconductor and a second region of the second semiconductor, and the second bond is one of:
a direct semiconductor/semiconductor bond, or
a metal-assisted semiconductor/semiconductor bond that includes a metal interface layer having a thickness of less than 100 Å, wherein the metal interface layer is between the second region of the first semiconductor and the second region of the second semiconductor.
14. The hybrid integrated optical device of claim 13 , wherein the first optical element is a waveguide.
15. The hybrid integrated optical device of claim 14 , further comprising an index matching material that optically couples the waveguide directly with the second optical element.
16. The hybrid integrated optical device of claim 13 , wherein:
the first pad comprises at least one of Ti, Cr, Pt, Ni or W; and
the second pad comprises at least one of Ti, Cr, Pt, Ni or W.
17. The hybrid integrated optical device of claim 13 , wherein the second semiconductor comprises a gain medium.
18. The hybrid integrated optical device of claim 17 , wherein:
the second bond is the direct semiconductor/semiconductor bond, and
the gain medium forms at least part of a light-emitting device that is operable to emit light through the direct semiconductor/semiconductor bond.
19. The hybrid integrated optical device of claim 13 , wherein:
the second bond is the metal-assisted semiconductor/semiconductor bond, and
the metal-assisted semiconductor/semiconductor bond provides an ohmic contact between the first semiconductor and the second semiconductor.