A method for forming a power semiconductor device is provided. The method includes: providing a semiconductor wafer grown by a Czochralski process and having a first side; forming an n-type substrate doping layer in the semiconductor wafer at the first side, the substrate doping layer having a doping concentration of at least 10.sup.17/cm.sup.3; and forming an epitaxy layer on the first side of the semiconductor wafer after forming the n-type substrate doping layer.

The present disclosure generally relates to methods of preparing spherical salt particles for industrial, medical, and other uses. The methods can include combining the angular salt particles with a quantity of finishing media, for example, into a receptacle. Thereafter, the angular salt particles and the finishing media can be moved or agitated until the angular salt particles have a desired sphericity.

The present disclosure generally relates to methods of preparing spherical salt particles for industrial, medical, and other uses. The methods can include combining the angular salt particles with a quantity of finishing media, for example, into a receptacle. Thereafter, the angular salt particles and the finishing media can be moved or agitated until the angular salt particles have a desired sphericity.

A method of performing spatial separation of different wavelengths in a single laser cavity includes generating, from a pump radiation source, pump radiations in spatially separate channels and focusing the generated pump radiations in the spatially separate channels towards an active gain medium having amplification spectra. The method also includes emitting from the active gain medium, amplified radiations of the spatially separate channels, each channel of the spatially separate channels representing a corresponding wavelength and focusing the emitted amplified radiations of the spatially separated channels towards an aperture. The method further includes suppressing, at the aperture, an off-axis mode of the amplified radiations of the spatially separate channels, diffracting the amplified radiations of the spatially separate channels received through the aperture to provide diffracted radiations and returning a portion of the diffracted radiations back to the aperture, and collimating the diffracted radiations of the spatially separate channel.

A method of performing spatial separation of different wavelengths in a single laser cavity includes generating, from a pump radiation source, pump radiations in spatially separate channels and focusing the generated pump radiations in the spatially separate channels towards an active gain medium having amplification spectra. The method also includes emitting from the active gain medium, amplified radiations of the spatially separate channels, each channel of the spatially separate channels representing a corresponding wavelength and focusing the emitted amplified radiations of the spatially separated channels towards an aperture. The method further includes suppressing, at the aperture, an off-axis mode of the amplified radiations of the spatially separate channels, diffracting the amplified radiations of the spatially separate channels received through the aperture to provide diffracted radiations and returning a portion of the diffracted radiations back to the aperture, and collimating the diffracted radiations of the spatially separate channel.

The present disclosure generally relates to systems and methods for growing group III-V nitride crystals. In particular the systems and methods include diffusing constituent species of the crystals through a porous body composed of the constituent species, where the species freely nucleate to grow large nitride crystals.

A system and method for providing support to semiconductor wafer is provided. An embodiment comprises introducing a vacancy enhancing material during the formation of a semiconductor ingot prior to the semiconductor wafer being separated from the semiconductor ingot. The vacancy enhancing material forms vacancies at a high density within the semiconductor ingot, and the vacancies form bulk micro defects within the semiconductor wafer during high temperature processes such as annealing. These bulk micro defects help to provide support and strengthen the semiconductor wafer during subsequent processing and helps to reduce or eliminate a fingerprint overlay that may otherwise occur.

A system and method for providing support to semiconductor wafer is provided. An embodiment comprises introducing a vacancy enhancing material during the formation of a semiconductor ingot prior to the semiconductor wafer being separated from the semiconductor ingot. The vacancy enhancing material forms vacancies at a high density within the semiconductor ingot, and the vacancies form bulk micro defects within the semiconductor wafer during high temperature processes such as annealing. These bulk micro defects help to provide support and strengthen the semiconductor wafer during subsequent processing and helps to reduce or eliminate a fingerprint overlay that may otherwise occur.

[Object]

It is an object of the present invention to provide a lithium tantalate single crystal substrate which undergoes only small warpage, is free from cracks and scratches, has better temperature non-dependence characteristics and a larger electromechanical coupling coefficient than a conventional Y-cut LiTaO.sub.3 substrate.

[Means to Solve the Problems]

The lithium tantalate single crystal substrate of the present invention is a rotated Y-cut LiTaO.sub.3 single crystal substrate having a crystal orientation of 36 Y-49 Y cut characterized in that: the substrate is diffused with Li from its surface into its depth such that it has a Li concentration profile showing a difference in the Li concentration between the substrate surface and the depth of the substrate; and the substrate is treated with single polarization treatment so that the Li concentration is substantially uniform from the substrate surface to a depth which is equivalent to 5-15 times the wavelength of either a surface acoustic wave or a leaky surface acoustic wave propagating in the LiTaO.sub.3 substrate surface.

[Object]

It is an object of the present invention to provide a lithium tantalate single crystal substrate which undergoes only small warpage, is free from cracks and scratches, has better temperature non-dependence characteristics and a larger electromechanical coupling coefficient than a conventional Y-cut LiTaO.sub.3 substrate.

[Means to Solve the Problems]

The lithium tantalate single crystal substrate of the present invention is a rotated Y-cut LiTaO.sub.3 single crystal substrate having a crystal orientation of 36 Y-49 Y cut characterized in that: the substrate is diffused with Li from its surface into its depth such that it has a Li concentration profile showing a difference in the Li concentration between the substrate surface and the depth of the substrate; and the substrate is treated with single polarization treatment so that the Li concentration is substantially uniform from the substrate surface to a depth which is equivalent to 5-15 times the wavelength of either a surface acoustic wave or a leaky surface acoustic wave propagating in the LiTaO.sub.3 substrate surface.