The disclosed technology generally relates to ferroelectric materials and semiconductor devices, and more particularly to semiconductor memory devices incorporating doped polar materials. In one aspect, a semiconductor device comprises a capacitor which in turn comprises a polar layer comprising a base polar material doped with a dopant. The base polar material includes one or more metal elements and one or both of oxygen or nitrogen. The dopant comprises a metal element that is different from the one or more metal elements and is present at a concentration such that a ferroelectric switching voltage of the capacitor is different from that of the capacitor having the base polar material without being doped with the dopant by more than about 100 mV. The capacitor stack additionally comprises first and second crystalline conductive oxide electrodes on opposing sides of the polar layer. The capacitor stack further comprises first and second barrier metal layers on respective ones of the first and second crystalline conductive oxide electrodes on opposing sides of the polar layer.

Methods and semiconductor devices are provided. A vertical junction field effect transistor (JFET) includes a substrate, an active region having a plurality of semiconductor fins, a source metal layer on an upper surface of the fins, a source metal pad layer coupled to the semiconductor fins through the source metal layer, a gate region surrounding the semiconductor fins, and a body diode surrounding the gate region.

Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.−2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.−2 or less, or 100 cm.sup.−2 or less, or 10 cm.sup.−2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.−2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.−2 or less, or 100 cm.sup.−2 or less, or 10 cm.sup.−2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

A compound semiconductor substrate and a method for manufacturing the same are provided to suppress surface roughness of a barrier layer while suppressing gate leak.

A method for manufacturing of a compound semiconductor substrate comprises a step forming an electronic traveling layer consisting of a first nitride semiconductor, a step forming a barrier layer consisting of a second nitride semiconductor with a wider band gap than a band gap of the first nitride semiconductor on the electronic traveling layer, and a step forming a cap layer with an organometallic vapor phase epitaxy on the barrier layer and in contact with the barrier layer. The cap layer has a C concentration of 5*10.sup.17 atoms/cm.sup.3 or more and 1*10.sup.20 atoms/cm.sup.3 or less, and consists of a nitride semiconductor. During the step forming the cap layer, source gas of the nitride semiconductor forming the cap layer and hydrocarbon gas are introduced to a top surface of the barrier layer.

A method may include thinning a silicon wafer to a particular thickness. The particular thickness may be based on a passband frequency spectrum of an adjustable optical filter. The method may also include covering a surface of the silicon wafer with an optical coating. The optical coating may filter an optical signal and may be based on the passband frequency spectrum. The method may additionally include depositing a plurality of thermal tuning components on the coated silicon wafer. The plurality of thermal tuning components may adjust a passband frequency range of the adjustable optical filter by adjusting a temperature of the coated silicon wafer. The passband frequency range may be within the passband frequency spectrum. The method may include dividing the coated silicon wafer into a plurality of silicon wafer dies. Each silicon wafer die may include multiple thermal tuning components and may be the adjustable optical filter.

A method may include thinning a silicon wafer to a particular thickness. The particular thickness may be based on a passband frequency spectrum of an adjustable optical filter. The method may also include covering a surface of the silicon wafer with an optical coating. The optical coating may filter an optical signal and may be based on the passband frequency spectrum. The method may additionally include depositing a plurality of thermal tuning components on the coated silicon wafer. The plurality of thermal tuning components may adjust a passband frequency range of the adjustable optical filter by adjusting a temperature of the coated silicon wafer. The passband frequency range may be within the passband frequency spectrum. The method may include dividing the coated silicon wafer into a plurality of silicon wafer dies. Each silicon wafer die may include multiple thermal tuning components and may be the adjustable optical filter.

A semiconductor structure, including a substrate, a first nitride layer, a polarity inversion layer, a second nitride layer, and a third nitride layer, is provided. The first nitride layer is located on the substrate. The polarity inversion layer is located on a surface of the first nitride layer to convert a non-metallic polarity surface of the first nitride layer into a metallic polarity surface of the polarity inversion layer. The second nitride layer is located on the polarity inversion layer. The third nitride layer is located on the second nitride layer. The substrate, the first nitride layer, the polarity inversion layer, and the second nitride layer include iron element.

A device includes a diode that includes a first group III-nitride (III-N) material and a transistor adjacent to the diode, where the transistor includes the first III-N material. The diode includes a second III-N material, a third III-N material between the first III-N material and the second III-N material, a first terminal including a metal in contact with the third III-N material, a second terminal coupled to the first terminal through the first group III-N material. The device further includes a transistor structure, adjacent to the diode structure. The transistor structure includes the first, second, and third III-N materials, a source and drain, a gate electrode and a gate dielectric between the gate electrode and each of the first, second and third III-N materials.

Methods for forming a semiconductor structure including a gallium nitride dipole layer are disclosed. An exemplary method includes using a cyclical deposition process to deposit a dipole layer comprising gallium nitride over a surface of a gate dielectric. The cyclical deposition process can include providing a gallium precursor to the reaction chamber and separately providing a nitrogen reactant to the reaction chamber. The cyclical deposition process may desirably be a thermal cyclical deposition process. Exemplary structures can include field effect transistor structures, such as gate all around structures.