Abstract: A method for fabricating a metastable crystalline structure is provided. The method includes providing a base substrate, wherein the base substrate comprises an insulating layer. The method further includes providing a metastable seed crystal on the base substrate, wherein the metastable seed crystal has a predefined metastable crystal phase or a predefined metastable composition. The method further includes forming a template structure above the base substrate, wherein the template structure covers at least a part of the metastable seed crystal. The method further includes growing the metastable crystalline structure with the predefined metastable crystal phase or the predefined metastable composition of the seed crystal inside the template structure. The growing of the metastable crystalline structure is nucleated from the seed crystal. Crystalline structures produced by the methods described herein are also provided.

Abstract: A method for fabricating a metastable crystalline structure is provided. The method includes providing a base substrate, wherein the base substrate comprises an insulating layer. The method further includes providing a metastable seed crystal on the base substrate, wherein the metastable seed crystal has a predefined metastable crystal phase or a predefined metastable composition. The method further includes forming a template structure above the base substrate, wherein the template structure covers at least a part of the metastable seed crystal. The method further includes growing the metastable crystalline structure with the predefined metastable crystal phase or the predefined metastable composition of the seed crystal inside the template structure. The growing of the metastable crystalline structure is nucleated from the seed crystal. Crystalline structures produced by the methods described herein are also provided.

Abstract: A method for fabricating an ellipsoidal or semi-ellipsoidal semiconductor structure includes steps of providing a semiconductor substrate and fabricating an ellipsoidal or semi-ellipsoidal cavity structure on the semiconductor substrate. The cavity structure encompasses a seed surface of the semiconductor substrate. The method includes a further step of growing the ellipsoidal or semi-ellipsoidal semiconductor structure within the ellipsoidal or semi-ellipsoidal cavity structure from the seed surface of the semiconductor substrate. Fabricating the cavity structure includes arranging a droplet comprising a sacrificial material on the semiconductor substrate, forming a layer of a coating material on the semiconductor substrate and the droplet, and selectively removing the sacrificial material of the droplet to expose the cavity structure.

Abstract: A method for fabricating an ellipsoidal or semi-ellipsoidal semiconductor structure includes steps of providing a semiconductor substrate and fabricating an ellipsoidal or semi-ellipsoidal cavity structure on the semiconductor substrate. The cavity structure encompasses a seed surface of the semiconductor substrate. The method includes a further step of growing the ellipsoidal or semi-ellipsoidal semiconductor structure within the ellipsoidal or semi-ellipsoidal cavity structure from the seed surface of the semiconductor substrate. Fabricating the cavity structure includes arranging a droplet comprising a sacrificial material on the semiconductor substrate, forming a layer of a coating material on the semiconductor substrate and the droplet, and selectively removing the sacrificial material of the droplet to expose the cavity structure.

Abstract: A method for fabricating a semiconductor substrate comprises providing a crystalline base substrate, forming an insulating layer on the crystalline base substrate and forming a trench in the insulating layer. This exposes a seed surface of the base substrate. The trench has sidewalls and a bottom. The bottom corresponds to the seed surface of the base substrate. The method further comprises growing, at a first growth step, an elongated seed structure in the trench from the seed surface of the substrate and forming a cavity structure above the insulating layer. The cavity structure covers the elongated seed structure and extends laterally to the elongated seed structure. The method comprises a further step of growing, at a second growth step, the semiconductor substrate in the cavity structure from the elongated seed structure. The invention is notably also directed to corresponding semiconductor structures and corresponding semiconductor substrates.

Abstract: A method for fabricating a semiconductor substrate comprises providing a crystalline base substrate, forming an insulating layer on the crystalline base substrate and forming a trench in the insulating layer. This exposes a seed surface of the base substrate. The trench has sidewalls and a bottom. The bottom corresponds to the seed surface of the base substrate. The method further comprises growing, at a first growth step, an elongated seed structure in the trench from the seed surface of the substrate and forming a cavity structure above the insulating layer. The cavity structure covers the elongated seed structure and extends laterally to the elongated seed structure. The method comprises a further step of growing, at a second growth step, the semiconductor substrate in the cavity structure from the elongated seed structure. The invention is notably also directed to corresponding semiconductor structures and corresponding semiconductor substrates.