Carrier bonded 1550 nm VCSEL with InP substrate removal
A vertical cavity surface emitting laser (VCSEL) structure includes a bottom distributed Bragg reflector (DBR) arranged over a substrate; a metal layer interposed between the bottom DBR and the substrate, wherein the metal layer and bottom DBR form a composite mirror structure. A patterned dielectric layer may be interposed between the metal layer and the bottom DBR to reduce a deleterious chemical reaction between the metal layer and the bottom DBR. The metal layer directly contacts a portion of the bottom DBR to enhance the electrical and thermal conductivity of the VCSEL structure.
1. A vertical cavity surface emitting laser (VCSEL) structure, comprising:
a metal layer arranged on a carrier substrate;
a dielectric layer arranged on the metal layer;
a lower semiconductor distributed Bragg reflector (DBR) arranged on the dielectric layer, wherein the lower semiconductor DBR contacts a portion of the metal layer and wherein the metal layer and the lower semiconductor DBR provide sufficient reflectivity to the VCSEL; and
an active region arranged on the lower semiconductor DBR.
2. The VCSEL structure of claim 1 , further comprising an upper reflector arranged on the active region.
3. The VCSEL structure of claim 1 , wherein the lower DBR includes
a first portion having a first thickness; and
a second portion having a second thickness, wherein the first thickness is greater than the second thickness.
4. The VCSEL structure of claim 3 , wherein the second portion surrounds the first portion.
5. The VCSEL structure of claim 1 , wherein a thickness of the dielectric layer is less than or equal to about one-half of a wavelength at which the active region lases.
6. The VCSEL structure of claim 1 , wherein the carrier substrate includes silicon.
7. The VCSEL structure of claim 1 , wherein the metal layer includes a metal mirror sub-layer adjacent the dielectric layer.
8. The VCSEL structure of claim 7 , wherein the metal mirror sub-layer includes at least one metal selected from the group consisting of gold, silver, copper, aluminum and combinations thereof.
9. The VCSEL structure of claim 1 , wherein the metal layer includes a metal bonding sub-layer adjacent the carrier substrate.
10. The VCSEL structure of claim 9 , wherein the metal bonding sub-layer includes at least one metal selected from the group consisting of gold, silver, copper, aluminum, indium, zinc and combinations thereof.
11. The VCSEL structure of claim 1 , wherein the metal layer includes a metal reaction barrier sub-layer.
12. The VCSEL structure of claim 11 , wherein the metal reaction barrier sub-layer includes at least one metal selected from the group consisting of titanium, tungsten, platinum and combinations thereof.
13. A vertical cavity surface emitting laser (VCSEL) comprising:
a metal layer having a first sub-layer and a second sub-layer, the second sub-layer having a melting point that allows the metal layer to bond to a carrier substrate;
a single dielectric layer arranged on the first sub-layer;
a lower semiconductor distributed Bragg reflector (DBR) arranged on the dielectric layer, wherein the lower semiconductor DBR contacts a portion of the metal layer;
an active region arranged on the lower semiconductor DBR;
wherein the second sub-layer has a melting point that enables the metal layer to bond to a carrier without substantially degrading the lower semiconductor DBR and wherein the single dielectric layer substantially prevents the metal layer from alloying the lower semiconductor DBR at least during formation of the metal layer.