Integrated photonics including germanium

Patent metadata

Field	Value
Publication number	US-2016197111-A1
Application number	US-201614987693-A
Country	US
Kind code	A1
Filing date	Jan 4, 2016
Priority date	Jan 5, 2015
Publication date	Jul 7, 2016
Grant date	—

Abstract

A photonic structure can include in one aspect one or more waveguides formed by patterning of waveguiding material adapted to propagate light energy. Such waveguiding material may include one or more of silicon (single-, poly-, or non-crystalline) and silicon nitride.

First claim

What is claimed is:

1 . A method of fabricating a photodetector structure comprising:
forming dielectric material over silicon; etching a trench in the dielectric material extending to the silicon; epitaxially growing germanium within the trench; annealing germanium formed by the epitaxially growing; repeating the epitaxially growing and the annealing until the germanium overfills the trench; planarizing an overfill portion of the germanium; and creating top and bottom contacts using doping and metallization.

2 . The method of claim 1 , wherein the epitaxially growing is performed so that germanium is formed on the-silicon.

3 . The method of claim 1 , wherein the epitaxially growing is performed so that the photodetector structure is absent a low-temperature SiGe or Ge buffer structure adjacent to the silicon.

4 . The method of claim 1 , wherein the epitaxially growing of germanium is performed without use of a doping gas so that intrinsic germanium is formed by the epitaxially growing.

5 . The method of claim 1 , wherein the epitaxially growing of germanium is performed using a dopant precursor so that in-situ doped germanium is formed by the epitaxially growing.

6 . The method of claim 1 , wherein the epitaxially growing includes performing epitaxial growing at a temperature in the range of from about 550 to about 850 degree Celsius.

7 . The method of claim 1 , wherein the epitaxially growing includes performing epitaxial growing at a temperature in the range of from about 550 to about 850 degree Celsius and wherein the annealing includes annealing at a temperature of between about 650 degrees Celsius to about 850 degrees Celsius.

8 . The method of claim 1 , wherein the epitaxially growing includes performing epitaxial growing at a temperature in the range of from about 550 to about 850 degree Celsius at a pressure in the range of from about 10 Torr to about 300 Torr using germane (GeH 4 ) and H 2 as a precursor and carrier gas, and wherein the annealing includes annealing at a temperature of between about 650 degrees Celsius to about 850 degrees Celsius at a pressure of between about 100 Torr to about 600 Torr.

9 . The method of claim 1 , wherein the growing is preceded by an ex-situ wet-chemical and an in-situ dry cleaning process for removal of organic and metallic contamination and native oxide.

10 . The method of claim 1 , wherein the growing is further preceded by an in-situ thermal treatment in a reducing Hz-environment for removal of sub-stoiciometric surface silicon oxide.

11 . The method of claim 1 , wherein the method includes performing a shallow top contact doping region and depositing a capping oxide.

12 . The method of claim 1 , wherein the method includes forming a reduced area doping region spaced apart from an oxide trench.

13 . The method of claim 1 , wherein the method includes forming a reduced area shallow top doping region spaced apart from an oxide trench so that there is defined spacing distance between a perimeter of the germanium and a perimeter of a doping region.

14 . The method of claim 1 , wherein the method includes forming a reduced area shallow top doping region spaced apart from an oxide trench by a spacing distance equal to or greater than a threshold distance.

15 . The method of claim 1 , wherein the method includes forming a reduced area top metal contact that is fully contained in a top doping region.

16 . The method of claim 1 , wherein the photonic structure is absent of a low-temperature SiGe or Ge buffer between the silicon and the germanium formation.

17 . A photonic structure comprising:
dielectric material formed over silicon; a trench formed in the dielectric material extending to the silicon; a germanium formation formed in the trench; and a doping region formed in an area of the germanium formation so that the doping region is spaced from the trench by a spacing distance equal to or greater than a threshold distance.

18 . The photonic structure of claim 17 , wherein an entire perimeter of the doping region is spaced from the trench by a spacing distance equal to or greater than a threshold distance.

19 . The photonic structure of claim 17 , wherein the threshold distance is selected from the group consisting of (a) 200 nm to 1000 nm and (b) 750 nm.

20 . The photonic structure of claim 17 , wherein the threshold distance is 750 nm.

21 . The photonic structure of claim 17 , further comprising a contact formed on the doping region in an area of the doping region so that the contact is spaced from a perimeter of the doping region by a spacing distance that is equal to or greater than a threshold distance.

22 . The photonic structure of claim 17 , further comprising a contact formed on the doping region in an area of the doping region so that an entire perimeter of the contact is spaced from a perimeter of the doping region by a spacing distance that is equal to or greater than a threshold distance.

23 . A photonic structure comprising:
silicon having a doping region; a germanium formation adapted to receive light transmitted by the silicon; an oppositely doped doping region formed on the germanium formation; a silicide formation formed on the doping region of the silicon; a conductive material formation formed on the silicide formation; and a conductive material formation formed on the germanium formation.

24 . The photonic structure of claim 23 , wherein the conductive material formation formed on the germanium formation is a germanide-free (refractory) conductive material formation.

Assignees

• Univ New York State Res Found

Inventors

• Coolbaugh Douglas
• Adam Thomas
• Leake Gerald L

Classifications

• H10P14/3441

  Conductivity type · CPC title

• H10P14/3411

  Silicon, silicon germanium or germanium · CPC title

• H10P14/3251

  consisting of three or more layers · CPC title

• H10P14/3211

  Silicon, silicon germanium or germanium · CPC title

• H10P14/2905

  Silicon, silicon germanium or germanium · CPC title