A three-dimensional stacked memory device provides uniform programming speeds for a block of memory cells. The channel layers of the memory strings which are relatively close to a local interconnect of a stack are doped to account for a reduced blocking oxide thickness. Channel layers of remaining memory strings are undoped. The doping can be performing by masking the channel layers which are to remain undoped while exposing the other memory holes to a dopant. The dopant can be provided, e.g., in a carrier gas, spin on glass or other solid, or by plasma doping. An n-type dopant such as antimony, arsenic or phosphorus may be used. Heating causes the dopants to diffuse into the channel layer. Another approach deposits doped silicon for some of the channel layers and undoped silicon for other channel layers.

Device structures for a FinFET and fabrication methods for making a device structure for a FinFET. A first layer containing a first dopant is formed on a first region of a substrate. A second layer containing a second dopant is formed on a second region of the substrate. A first plurality of fins are formed and are each located in a respective trench extending from the substrate through the first layer. A second plurality of fins are formed and are each located in a respective trench extending from the substrate through the second layer. The first dopant is transferred from the first layer to a first section in each of the first plurality of fins and the second dopant is transferred from the second layer to a first section in each of the second plurality of fins.

A method of making a semiconductor device includes forming a first fin of a first transistor in a substrate; forming a second fin of a second transistor in the substrate; disposing a first doped oxide layer including a first dopant onto the first fin and the second fin, the first dopant being an n-type dopant or a p-type dopant; disposing a mask over the first fin and removing the first doped oxide layer from the second fin; removing the mask and disposing a second doped oxide layer onto the first doped oxide layer over the first doped oxide layer covering the first fin and directly onto the second fin, the second doped oxide layer including an n-type dopant or a p-type dopant that is different than the first dopant; and annealing to drive in the first dopant into a portion of the first fin and the second dopant into a portion of the second fin.

A method for fabricating a trench Schottky rectifier device is provided. At first, a plurality of trenched are formed in a substrate of a first conductivity type. An insulating layer is formed on sidewalls of the trenches. Then, an ion implantation procedure is performed through the trenches to form a plurality of doped regions of a second conductivity type under the trenches. Subsequently, the trenches are filled with conductive structure such as metal structure or tungsten structure. At last, an electrode overlying the conductive structure and the substrate is formed. Thus, a Schottky contact appears between the electrode and the substrate. Each doped region and the substrate will form a PN junction to pinch off current flowing toward the Schottky contact to suppress the current leakage in a reverse bias mode.

Conductivity improvements in III-V semiconductor devices are described. A first improvement includes a barrier layer that is not coextensively planar with a channel layer. A second improvement includes an anneal of a metal/Si, Ge or SiliconGermanium/III-V stack to form a metal-Silicon, metal-Germanium or metal-SiliconGermanium layer over a Si and/or Germanium doped III-V layer. Then, removing the metal layer and forming a source/drain electrode on the metal-Silicon, metal-Germanium or metal-SiliconGermanium layer. A third improvement includes forming a layer of a Group IV and/or Group VI element over a III-V channel layer, and, annealing to dope the III-V channel layer with Group IV and/or Group VI species. A fourth improvement includes a passivation and/or dipole layer formed over an access region of a III-V device.

A method is provided for forming an ultra-shallow boron doping region in a semiconductor device. The method includes depositing a diffusion filter layer on a substrate, the diffusion filter containing a boron nitride layer, a boron oxynitride layer, a silicon nitride layer, or a silicon oxynitride layer, and depositing a boron dopant layer on the diffusion filter layer, the boron dopant layer containing boron oxide, boron oxynitride, or a combination thereof, with the proviso that the diffusion filter layer and the boron dopant layer do not contain the same material. The method further includes heat-treating the substrate to form the ultra-shallow boron dopant region in the substrate by controlled diffusion of boron from the boron dopant layer through the diffusion filter layer and into the substrate.

A method for making a self-aligned vertical nanosheet field effect transistor. A vertical trench is etched in a layered structure including a plurality of layers, using reactive ion etching, and filled, using an epitaxial process, with a vertical semiconductor nanosheet. A sacrificial layer from among the plurality of layers is etched out and replaced with a conductive (e.g., metal) gate layer coated with a high-dielectric-constant dielectric material. Two other layers from among the plurality of layers, one above and one below the gate layer, are doped, and act as dopant donors for a diffusion process that forms two PN junctions in the vertical semiconductor nanosheet.

A reverse-blocking IGBT (insulated gate bipolar transistor) includes a plurality of IGBT cells disposed in a device region of a semiconductor substrate, a reverse-blocking edge termination structure disposed in a periphery region of the semiconductor substrate which surrounds the device region, one or more trenches formed in the periphery region between the reverse-blocking edge termination structure and an edge face of the semiconductor substrate, a p-type dopant source at least partly filling the one or more trenches, and a continuous p-type doped region disposed in the periphery region and formed from p-type dopants out-diffused from the p-type dopant source. The continuous p-type doped region extends from a top surface of the semiconductor substrate to a bottom surface of the semiconductor substrate.

A method for doping fins includes depositing a first dopant layer at a base of fins formed in a substrate, depositing a dielectric layer on the first dopant layer and etching the dielectric layer and the first dopant layer in a first region to expose the substrate and the fins. A second dopant layer is conformally deposited over the fins and the substrate in the first region. The second dopant layer is recessed to a height on the fins in the first region. An anneal is performed to drive dopants into the fins from the first dopant layer in a second region and from the second dopant layer in the first region to concurrently form punch through stoppers in the fins and wells in the substrate.

A method for channel formation in a fin transistor includes removing a dummy gate and dielectric from a dummy gate structure to expose a region of an underlying fin and depositing an amorphous layer including Ge over the region of the underlying fin. The amorphous layer is oxidized to condense out Ge and diffuse the Ge into the region of the underlying fin to form a channel region with Ge in the fin.