1. A method of manufacturing a semiconductor laser device comprising:
depositing a first cladding layer over a substrate;
depositing an active region on said first cladding layer;
depositing a second cladding layer on said active region;
removing a portion of each of said first cladding layer, said active region and said second cladding layer to form a mesa region having a top portion and a side portion, such that all of said first cladding layer that extends beyond said active region and said second cladding layer of said mesa region is removed to thereby enhance heat dissipation capability through the substrate;
depositing an insulator layer on the side portion of said mesa region; and
depositing a metal layer to cover the top portion of said mesa region and said insulator layer which is dimensioned and configured to have a thickness at least half a thickness of said mesa region and to laterally spread heat away from said active region.
2. The method of claim 1, wherein the step of removing a portion of each of said first cladding layer, said active region and said second cladding layer comprises an etching process.
3. The method of claim 1, wherein the step of depositing a metal layer comprises:
evaporating a thin metal contact layer over said insulating layer; and
applying a thicker electroplated metal layer upon the thin metal contact layer.
4. The method of claim 3, further including the steps of:
evaporating a metal contact layer onto an underside of the substrate; and
applying a bonding layer to the metal contact layer.
5. The method of claim 4, further including the steps of:
applying a heat sink to the bonding layer; and
attaching wire connectors to the metal contact layer.
6. The method of claim 3, wherein:
the first cladding layer is InAsAlSb;
the second cladding layer is InAsAlSb;
the thin metal contact layer is AuTi; and
the thicker electroplated layer is gold.
7. The method of claim 1, wherein:
the step of depositing an insulator layer includes applying said insulator layer on the top portion of said mesa region.
8. The method of claim 1, wherein the step of removing a portion of each of said first cladding layer, said active region and said second cladding layer transgresses the entire thickness of said first cladding layer, said active region, and said second cladding layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A heating mould for thermal nanoimprint lithography comprising:
a substrate having a first principal surface and a second principal surface, and a through-cavity extending from a first orifice in the first principal surface up to a second orifice in the second principal surface, said first principal surface being at least partially covered by a first membrane, and said second orifice being completely closed off by a second electrically and thermally insulating membrane with a first disposed in contact with said second principal surface and at least partially covering said second surface;
a thermally conducting layer that mechanically supports the second membrane on said first side of the second membrane above said second orifice;
an insulating layer disposed beneath said thermally conducting mechanical support layer;
heating means disposed on a second side of said second membrane in a zone of said second membrane above said second orifice;
an electrically and thermally insulating layer which covers said heating means and, at least partially, said second membrane;
imprint patterns disposed on said electrically and thermally insulating layer in a zone of said electrically and thermally insulating layer above said second orifice; and
means for supplying an electric current to said heating means.
2. The mould according to claim 1, in which said first and second principal surfaces are planar and parallel.
3. The mould according to claim 2, in which said first and second principal surfaces are horizontal.
4. The mould according to claim 1, further comprising alignment marks.
5. The mould according to claim 4, in which said alignment marks are located in the second membrane, in said electrically and thermally insulating layer, or on said electrically and thermally insulating layer near the imprint patterns, or a combination thereof.
6. The mould according to claim 1, in which the substrate is made of a material chosen from among a group of materials compatible with microfabrication and nanofabrication processes including silicon, silicon oxide, silicon nitride, germanium, sapphire, GaAs, and composite materials comprising several of these materials.
7. The mould according to claim 1, in which the first and second membranes are made of a material resistant to anisotropic etching of the substrate material.
8. The mould according to claim 1, in which the heating means are made of a material chosen from among platinum, titanium nitride, single-crystal silicon, polycrystalline silicon and all the conductive materials compatible with microfabrication and nanofabrication technologies.
9. The mould according to claim 1, in which the electrically and thermally insulating layer is made of a material chosen from SiO2, Si3N4, Al2O3, HfO2, and all the electrically and thermally insulating materials compatible with microfabrication and nanofabrication technologies.
10. The mould according to claim 1, in which the imprint patterns are made of a material chosen from Si, SiO2, Si3N4, Al2O3, HfO2, and all the materials compatible with microfabrication and nanofabrication technologies.
11. A process for producing a mould according to claim 1, the process comprising the following steps performed in succession:
a. forming a thermally conducting and mechanical support layer in a zone of a first principal surface of a substrate;
b. depositing a first membrane on a second principal surface of the substrate;
c. depositing a second electrically and thermally insulating membrane on said first principal surface;
d. depositing an electrically resistive heating layer on a zone of the second membrane above the thermally conducting and mechanical support layer;
e. shaping the electrically resistive heating layer;
f. depositing an electrically and thermally insulating layer on said shaped, electrically resistive heating layer and onto the second membrane;
g. producing imprint patterns on said electrically and thermally insulating layer;
h. forming at least one lead for supplying electric current to the electrically resistive heating layer; and
i. etching the first membrane, then forming a cavity in the substrate from a first orifice in the second principal surface up to the thermally conducting mechanical support layer, in a zone of the first principal surface.
12. The process according to claim 11, in which the at least one electric current lead is fabricated by etching at least one via through the first membrane, through the second membrane, or through the substrate, or a combination thereof, and by filling the at least one via by electrodeposition.
13. A process for producing a substrate comprising a nanostructured surface by thermal nanoimprint lithography, in which the mould according to claim 1 is employed.
14. The process according to claim 11, further comprising:
forming alignment or positioning marks are produced in the membrane layer, in the insulating layer, or on said electrically and thermally insulating layer near the imprint patterns.
15. The mould according to claim 7, wherein the substrate is made of silicon and the first and second membranes are made from Si3N4.
16. The mould according to claim 1, wherein said first membrane completely closes off said first orifice.
17. The mould according to claim 1, wherein said first membrane completely partially closes off said first orifice.
18. The mould according to claim 1, wherein said first membrane is disposed so as to not cover any portion of said first orifice.