Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

A substrate 10 contains a first layer L1 and a second layer L2 that are stacked on one another, the first layer L1 contains crystalline AlN and an additive element, the second layer L2 contains crystalline α-alumina, the additive element is at least one selected from the group consisting of rare earth elements, alkaline earth elements, and alkali metal elements, the thickness of the first layer L1 is 5 to 600 nm, RC(002) is a rocking curve of diffracted X-rays originating from a (002) plane of AlN, RC(002) is measured by an ω-scan of the surface S.sub.L1 of the first layer L1, the half width of RC(002) is 0° to 0.4°, RC(100) is a rocking curve of diffracted X-rays originating from a (100) plane of AlN, RC(100) is measured by a ϕ-scan of the surface S.sub.L1 of the first layer L1, and the half width of RC(100) is 0° to 0.8°.

An epitaxial wafer and a method of fabricating an epitaxial wafer, the method including providing a semiconductor substrate doped with both boron and germanium such that a sum of boron concentration and germanium concentration is at least 8.5E+18 atoms/cm.sup.3 and the germanium concentration is 6 times or less the boron concentration; forming an epitaxial layer on the semiconductor substrate such that the semiconductor substrate and the epitaxial layer constitute the epitaxial wafer; and annealing the epitaxial wafer for 1 hour or longer at a temperature of 1,000° C. or less.

A transparent timepiece component, in particular a watch glass, has a substantially planar or curved interior surface, and has mainly a transparent material colored by a zone of modified chemical composition within the component through an introduction of at least one coloring chemical element of the transparent material, this zone of modified chemical composition extending in one part only of the total thickness of the timepiece component.

An epitaxial wafer and a method of fabricating an epitaxial wafer, the method including providing a semiconductor substrate doped with both boron and germanium such that a sum of boron concentration and germanium concentration is at least 8.5E+18 atoms/cm.sup.3 and the germanium concentration is 6 times or less the boron concentration; forming an epitaxial layer on the semiconductor substrate such that the semiconductor substrate and the epitaxial layer constitute the epitaxial wafer; and annealing the epitaxial wafer for 1 hour or longer at a temperature of 1,000 C. or less.

In some embodiments, a selective cyclic (optionally dry) etching of a first surface of a substrate relative to a second surface of the substrate in a reaction chamber by chemical atomic layer etching comprises forming a modification layer using a first plasma and etching the modification layer. The first surface comprises carbon and/or nitride and the second surface does not comprise carbon and/or nitride.

In some embodiments, a selective cyclic (optionally dry) etching of a first surface of a substrate relative to a second surface of the substrate in a reaction chamber by chemical atomic layer etching comprises forming a modification layer using a first plasma and etching the modification layer. The first surface comprises carbon and/or nitride and the second surface does not comprise carbon and/or nitride.