Described herein are rock salt substrates and methods of making thereof that are useful as epitaxial substrates for semiconducting materials, including ultra-wide bandgap materials. Advantageously, the described rock salt substrates may be useful as substrates for Group III (Al, Ga, In)—N substrate allowing for pseudomorphic growth of novel, desirable materials. The rock salt may be provided as a bulk material or deposited as a thin film. These substrates may allow for generation of high Al content semiconductor devices with ultra-wide bandgap and other useful properties.

A method of fabricating a semiconductor device includes implanting dopants into a silicon substrate, and performing a thermal anneal process that activates the implanted dopants. In response to activating the implanted dopants, a layer of ultra-thin single-crystal silicon is formed in a portion of the silicon substrate. The method further includes performing a heteroepitaxy process to grow a semiconductor material from the layer of ultra-thin single-crystal silicon.

Examples herein relate to devices having substrates with selective airgap regions for mitigating defects resulting from heteroepitaxial growth of device materials. An example device may include a first semiconductor layer disposed on a substrate. The first semiconductor layer may have a window cut through a face, where etching a selective airgap region on the substrate is enabled via the window. A second semiconductor layer may be heteroepitaxially grown on the face of the first semiconductor layer so that at least a portion of the second semiconductor layer is aligned over the selective air gap region.

Some embodiments include methods of forming voids within semiconductor constructions. In some embodiments the voids may be utilized as microstructures for distributing coolant, for guiding electromagnetic radiation, or for separation and/or characterization of materials. Some embodiments include constructions having micro-structures therein which correspond to voids, conduits, insulative structures, semiconductor structures or conductive structures.

Some embodiments include methods of forming voids within semiconductor constructions. In some embodiments the voids may be utilized as microstructures for distributing coolant, for guiding electromagnetic radiation, or for separation and/or characterization of materials. Some embodiments include constructions having micro-structures therein which correspond to voids, conduits, insulative structures, semiconductor structures or conductive structures.

The invention is a special designed pattern heterogeneous substrate, which is epitaxially deposited on a heterogeneous substrate by two step growth, and a thermal cycle annealing is added to reduce the lattice mismatch between the layers and the difference in thermal expansion coefficient, thereby obtaining a better stress. The quality of the semiconductor epitaxial layer is improved, and the present invention can easily grasp the timing of stress release when the semiconductor is grown on the heterogeneous substrate, avoid cracks in the semiconductor epitaxial layer, and form a crack free zone in the middle of the semiconductor epitaxial layer.

Some embodiments include methods of forming voids within semiconductor constructions. In some embodiments the voids may be utilized as microstructures for distributing coolant, for guiding electromagnetic radiation, or for separation and/or characterization of materials. Some embodiments include constructions having micro-structures therein which correspond to voids, conduits, insulative structures, semiconductor structures or conductive structures.

There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient is approximately expressed by equation (1) in a wavelength range of at least 1 m or more and 3.3 m or less: =n K.sup.a (1) (wherein, (m) is a wavelength, (cm.sup.1) is absorption coefficient of the nitride crystal substrate at 27 C., n (cm.sup.3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.510.sup.19K6.010.sup.19, a=3).

Some embodiments include methods of forming voids within semiconductor constructions. In some embodiments the voids may be utilized as microstructures for distributing coolant, for guiding electromagnetic radiation, or for separation and/or characterization of materials. Some embodiments include constructions having micro-structures therein which correspond to voids, conduits, insulative structures, semiconductor structures or conductive structures.

Some embodiments include methods of forming voids within semiconductor constructions. In some embodiments the voids may be utilized as microstructures for distributing coolant, for guiding electromagnetic radiation, or for separation and/or characterization of materials. Some embodiments include constructions having micro-structures therein which correspond to voids, conduits, insulative structures, semiconductor structures or conductive structures.