Abstract: A germanium-on-silicon photodetector is fabricated by forming a thin silicon oxide layer on a silicon layer, and then forming a silicon nitride layer on the silicon oxide layer. A nitride dry etch process is used to etch an opening through the silicon nitride layer (through a photoresist mask). The nitride dry etch is stopped on the thin silicon oxide layer, preventing damage to the underlying silicon layer. A wet etch is then performed through the opening in the silicon nitride layer to remove the exposed silicon oxide layer. The wet etch exposes (and cleans) a portion of the underlying silicon layer. High-quality germanium is epitaxially grown over the exposed portion of the silicon layer, thereby providing a germanium structure that forms the intrinsic region of a PIN photodiode.

Abstract: A photonics integrated circuit includes a first waveguide and a second waveguide. A portion of the first waveguide has a first cladding with a first refractive index. The second waveguide includes a second cladding with a second refractive index different from the first refractive index. Also disclosed is a test circuit for a photonics integrated circuit. The test circuit can be used to determine waveguide losses, and used to tune the waveguide losses.

Abstract: There are disclosed various implementations of an anode over cathode germanium and silicon photodiode including an N type silicon region formed in a silicon substrate, the N type silicon region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type silicon region, the P type germanium region being an anode of the photodiode. An anode contact of the photodiode is situated over the P type germanium region providing the anode. In some implementations, silicided cathode contacts are formed over the N type silicon region providing the cathode. In some implementations, a P type silicon cap is formed over the P type germanium region. In those implementations, a silicided anode contact may be situated on the P type silicon cap.

Abstract: There are disclosed herein various implementations of a photodiode including a silicon substrate, and an N type germanium region situated over the silicon substrate, the N type germanium region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type germanium region, the P type germanium region being an anode of the photodiode. The photodiode also includes a P type silicon cap over the P type germanium region, an anode contact of the photodiode situated on the P type silicon cap, and one or more cathode contacts of the photodiode electrically connected to the N type germanium region.

Abstract: There are disclosed herein various implementations of a photodiode including a silicon substrate, and an N type germanium region situated over the silicon substrate, the N type germanium region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type germanium region, the P type germanium region being an anode of the photodiode. The photodiode also includes a P type silicon cap over the P type germanium region, an anode contact of the photodiode situated on the P type silicon cap, and one or more cathode contacts of the photodiode electrically connected to the N type germanium region.

Abstract: There are disclosed herein various implementations of a photodiode including a silicon substrate, and an N type germanium region situated over the silicon substrate, the N type germanium region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type germanium region, the P type germanium region being an anode of the photodiode. The photodiode also includes a P type silicon cap over the P type germanium region, an anode contact of the photodiode situated on the P type silicon cap, and one or more cathode contacts of the photodiode electrically connected to the N type germanium region.

Abstract: There are disclosed various implementations of an anode over cathode germanium and silicon photodiode including an N type silicon region formed in a silicon substrate, the N type silicon region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type silicon region, the P type germanium region being an anode of the photodiode. An anode contact of the photodiode is situated over the P type germanium region providing the anode. In some implementations, silicided cathode contacts are formed over the N type silicon region providing the cathode. In some implementations, a P type silicon cap is formed over the P type germanium region. In those implementations, a silicided anode contact may be situated on the P type silicon cap.

Abstract: There are disclosed herein various implementations of a photodiode including a silicon substrate, and an N type germanium region situated over the silicon substrate, the N type germanium region being a cathode of the photodiode. In addition, the photodiode includes a P type germanium region situated over the N type germanium region, the P type germanium region being an anode of the photodiode. The photodiode also includes a P type silicon cap over the P type germanium region, an anode contact of the photodiode situated on the P type silicon cap, and one or more cathode contacts of the photodiode electrically connected to the N type germanium region.

Abstract: A germanium-on-silicon photodetector is fabricated by forming a thin silicon oxide layer on a silicon layer, and then forming a silicon nitride layer on the silicon oxide layer. A nitride dry etch process is used to etch an opening through the silicon nitride layer (through a photoresist mask). The nitride dry etch is stopped on the thin silicon oxide layer, preventing damage to the underlying silicon layer. A wet etch is then performed through the opening in the silicon nitride layer to remove the exposed silicon oxide layer. The wet etch exposes (and cleans) a portion of the underlying silicon layer. High-quality germanium is epitaxially grown over the exposed portion of the silicon layer, thereby providing a germanium structure that forms the intrinsic region of a PIN photodiode.

Abstract: A semiconductor structure comprising aluminum oxide. The semiconductor structure comprises a dielectric material overlying a substrate. The aluminum oxide overlies the dielectric material in a first region of the structure. A second region of the structure includes a first titanium nitride portion overlying the dielectric material, magnesium over the first titanium nitride portion, and a second titanium nitride portion over the magnesium. Methods of forming the semiconductor structure including aluminum oxide are also disclosed.

Abstract: A semiconductor structure comprising aluminum oxide. The semiconductor structure comprises a dielectric material overlying a substrate. The aluminum oxide overlies the dielectric material in a first region of the structure. A second region of the structure includes a first titanium nitride portion overlying the dielectric material, magnesium over the first titanium nitride portion, and a second titanium nitride portion over the magnesium. Methods of forming the semiconductor structure including aluminum oxide are also disclosed.

Abstract: Composite hydrogels and methods for making and using the composite hydrogels are provided. The composite hydrogels comprise graphene oxide flakes distributed in, and covalently bonded to, a thermo-responsive hydrogel polymer.

Abstract: A semiconductor structure comprising aluminum oxide. The semiconductor structure comprises a dielectric material overlying a substrate. The aluminum oxide overlies the dielectric material in a first region of the structure. A second region of the structure includes a first titanium nitride portion overlying the dielectric material, magnesium over the first titanium nitride portion, and a second titanium nitride portion over the magnesium. Methods of forming the semiconductor structure including aluminum oxide are also disclosed.

Abstract: A semiconductor structure comprising aluminum oxide. The semiconductor structure comprises a dielectric material overlying a substrate. The aluminum oxide overlies the dielectric material in a first region of the structure. A second region of the structure includes a first titanium nitride portion overlying the dielectric material, magnesium over the first titanium nitride portion, and a second titanium nitride portion over the magnesium. Methods of forming the semiconductor structure including aluminum oxide are also disclosed.

Abstract: Composite hydrogels and methods for making and using the composite hydrogels are provided. The composite hydrogels comprise graphene oxide flakes distributed in, and covalently bonded to, a thermo-responsive hydrogel polymer.