A method includes etching a first recess adjacent a first dummy gate stack and a first fin; etching a second recess adjacent a second dummy gate stack and a second fin; and epitaxially growing a first epitaxy region in the first recess. The method further includes depositing a first metal-comprising mask over the first dummy gate stack, over the second dummy gate stack, over the first epitaxy region in the first recess, and in the second recess; patterning the first metal-comprising mask to expose the first dummy gate stack and the first epitaxy region; epitaxially growing a second epitaxy region in the first recess over the first epitaxy region; and after epitaxially growing the second epitaxy region, removing remaining portions of the first metal-comprising mask.

There is provided a gallium nitride single crystal substrate, which is a gallium nitride single crystal substrate having a diameter of 50 mm or more, with a low-index crystal plane closest to a main surface being (0001), and in which Ge concentration in the substrate is 310.sup.18 cm.sup.3 or more; and among peaks appearing in a histogram of diameters of etch pits during etching applied to the main surface with an alkaline etching solution, a first peak having a smallest diameter is a single peak having no shoulder.

The present disclosure provides a method for preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology. The method includes: preparing a metal mask ring on a composite epitaxial substrate, epitaxially growing a GaN single-crystal sacrificial layer in a confined manner, performing separation with interlayer decoupling of single-crystal graphene through an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer, epitaxially growing a GaN single-crystal thick film in a diameter expanded manner, and performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate. The metal mask ring is compatible with the GaN single-crystal preparation process (hydride vapor phase epitaxy (HVPE)), and efficiently catalyzes decomposition reaction of the nitrogen source. While prohibiting edge growth of the GaN single-crystal thick film, the present disclosure improves a crystalline quality of the GaN single-crystal substrate.

A method of forming regrown fiducials includes providing a III-V compound substrate having a device region and an alignment mark region. The III-V compound substrate is characterized by a processing surface. The method also includes forming a hardmask layer having a first set of openings in the device region exposing a first surface portion of the processing surface of the III-V compound substrate and a second set of openings in the alignment mark region exposing a second surface portion of the processing surface and etching the first surface portion and the second surface portion of the III-V compound substrate using the hardmask layer as a mask to form a plurality of trenches. The method also includes epitaxially regrowing a semiconductor layer in the trenches to form the regrown fiducials extending to a predetermined height over the processing surface in the alignment mark region.

The present disclosure provides a method for preparing a gallium nitride (GaN) single-crystal substrate with an edge metal mask technology. The method includes: preparing a metal mask ring on a composite epitaxial substrate, epitaxially growing a GaN single-crystal sacrificial layer in a confined manner, performing separation with interlayer decoupling of single-crystal graphene through an in-situ temperature gradient method to obtain a self-supporting GaN single-crystal sacrificial layer, epitaxially growing a GaN single-crystal thick film in a diameter expanded manner, and performing chemico-mechanical trimming on the GaN single-crystal thick film to obtain a stress-free self-supporting GaN single-crystal substrate. The metal mask ring is compatible with the GaN single-crystal preparation process (hydride vapor phase epitaxy (HVPE)), and efficiently catalyzes decomposition reaction of the nitrogen source. While prohibiting edge growth of the GaN single-crystal thick film, the present disclosure improves a crystalline quality of the GaN single-crystal substrate.

A finFET device includes a doped source and/or drain extension that is disposed between a gate spacer of the finFET and a bulk semiconductor portion of the semiconductor substrate on which the n-doped or p-doped source or drain extension is disposed. The doped source or drain extension is formed by a selective epitaxial growth (SEG) process in a cavity formed proximate the gate spacer. After formation of the cavity, advanced processing controls (APC) (i.e., integrated metrology) is used to determine the distance of recess, without exposing the substrate to an oxidizing environment. The isotropic etch process, the metrology, and selective epitaxial growth may be performed in the same platform.

A method for manufacturing a silicon substrate for a quantum computer, the method includes the steps of forming a Si epitaxial layer by epitaxial growth using a Si source gas as a silicon-based raw material gas, in which a total content of 28Si and 30Si in a whole silicon contained in the silicon-based raw material gas is 99.9% or more, on a silicon substrate, forming an oxygen (O) -doped layer by oxidizing a surface of the Si epitaxial layer, and forming a Si epitaxial layer by epitaxial growth using a Si source gas, in which a total content of 28Si and 30Si in a whole silicon contained in the silicon-based raw material gas is 99.9% or more, on the -doped layer.

Apparatus and methods to process one or more wafers are described. A spatial deposition tool comprises a plurality of substrate support surfaces on a substrate support assembly and a plurality of spatially separated and isolated processing stations. The spatially separated isolated processing stations have independently controlled temperature, processing gas types, and gas flows. In some embodiments, the processing gases on one or multiple processing stations are activated using plasma sources. The operation of the spatial tool comprises rotating the substrate assembly in a first direction, and rotating the substrate assembly in a second direction, and repeating the rotations in the first direction and the second direction until a predetermined thickness is deposited on the substrate surface(s).

Embodiments according to the present invention provide a method for manufacturing a GaN HEMT power semiconductor epitaxy wafer having a high-quality, high-resistance buffer region, comprising: a first GaN buffer layer formation step in which carbon is doped using a metal-organic source among sources supplied for GaN growth as a precursor for carbon doping; and a second GaN buffer layer formation step in which carbon is doped by supplying a precursor for carbon doping separately from the sources supplied for GaN growth; wherein the precursor for carbon doping in the second GaN buffer layer formation step is at least one of CH.sub.4 (methane), C.sub.2H.sub.4 (ethylene), C.sub.2H.sub.2 (acetylene), C.sub.3H.sub.8 (propane), i-C.sub.4H.sub.10 (iso-butane), and [N(CH.sub.3).sub.3] (trimethylamine).

The present invention pertains to a process for direct deposition of graphene oxide onto a substrate of interest from a gaseous source of at least one carbon precursor, using a plasma-enhanced chemical vapor deposition method. It is also directed to a device for implementing this process.