Process for fabricating an optoelectronic device comprising a germanium-on-silicon photodiode optically coupled to an integrated Si3N4 waveguide
AssigneeCommissariat A L'energie Atomique Et Aux Energies Alternatives
InventorBertrand Szelag
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Abstract
A process for fabricating an optoelectronic device having a germanium-on-silicon photodiode coupled to an Si3N4 waveguide includes producing a semiconductor substrate having a semiconductor stack of thin layers configured to form segments of a semiconductor structure of the photodiode, producing a photonic substrate having the Si3N4 waveguide, and transferring and bonding the semiconductor substrate to the photonic substrate. The photodiode is produced by photolithography and etching of the semiconductor stack to form the semiconductor structure which is then located above the waveguide.
Claims18
A process for fabricating an optoelectronic device comprising a germanium-on-silicon photodiode optically coupled to an Si3N4 waveguide, the photodiode comprising a semiconductor structure formed from a lower doped segment that is based on a silicon material doped a first conductivity type, an upper segment that is doped a second conductivity type opposite the first type and that is based on silicon and/or germanium, and an intermediate absorbing segment that is based on germanium and located between the lower and upper doped segments along a thickness axis of the photodiode, the process comprising:
- producing a semiconductor substrate comprising a semiconductor stack of thin layers configured to form the segments of the semiconductor structure;
- producing a photonic substrate comprising a carrier layer and comprising the waveguide, producing the photonic substrate comprising producing the waveguide from a stoichiometric silicon nitride Si3N4, followed by annealing the waveguide at a temperature at least equal to 1000° C.;
- transferring and bonding the semiconductor substrate to the photonic substrate after the annealing;
- and
- producing the photodiode by photolithography and etching the semiconductor stack to form the semiconductor structure which is located above the waveguide.
An optoelectronic device, comprising:
- a germanium-on-silicon photodiode comprising a semiconductor structure formed from a lower doped segment that is based on silicon, an upper doped segment, and an intermediate absorbing segment that is based on germanium and located between the lower and upper doped segments along a thickness axis of the photodiode;
- and
- a photonic substrate comprising:
- an Si3N4 waveguide;
- and
- an intermediate dielectric layer covering the waveguide and a lower dielectric layer on which the waveguide rests,
- wherein the waveguide is located below the photodiode along a thickness axis of the photodiode, and is integrated into the photonic substrate,
- wherein the photodiode is attached to the intermediate dielectric layer of the photonic substrate via a direct bonding process, and
- wherein the waveguide is optically coupled to the photodiode evanescently via the intermediate dielectric layer.
An optoelectronic device, comprising:
- a germanium-on-silicon photodiode comprising a semiconductor structure formed from a lower doped segment that is based on silicon, an upper doped segment, and an intermediate absorbing segment that is based on germanium and located between the lower and upper doped segments along a thickness axis of the photodiode;
- and
- an Si3N4 waveguide integrated into and optically coupled to the photodiode;
- wherein the waveguide is located below the photodiode along a thickness axis of the photodiode, and is integrated into a photonic substrate on which the photodiode rests,
- the device comprising:
- an intermediate dielectric layer covering the waveguide and a lower dielectric layer on which the waveguide rests,
- wherein the waveguide is optically coupled to the photodiode evanescently via the intermediate dielectric layer, and
- wherein the lower doped segment has a transverse dimension larger than that of the intermediate absorbing segment, spacers that are based on an electrically insulating material being placed against flanks of the intermediate absorbing segment and extending over one portion of an upper face of the lower doped segment.
Dependencies are inferred from the claim text.