A silicon carbide epitaxial layer includes a first silicon carbide layer, a second silicon carbide layer, a third silicon carbide layer, and a fourth silicon carbide layer. A nitrogen concentration of the second silicon carbide layer is increased from the first silicon carbide layer toward the third silicon carbide layer. A value obtained by dividing, by a thickness of the second silicon carbide layer, a value obtained by subtracting a nitrogen concentration of the first silicon carbide layer from a nitrogen concentration of the third silicon carbide layer is less than or equal to 6×10.sup.23 cm.sup.−4. Assuming that the nitrogen concentration of the third silicon carbide layer is N cm.sup.−3; and a thickness of the third silicon carbide layer is X μm, X and N satisfy a Formula 1.

A semiconductor device includes a semiconductor layer of a first conductivity type. A well region that is a second conductivity type well region is formed on a surface layer portion of the semiconductor layer and has a channel region defined therein. A source region that is a first conductivity type source region is formed on a surface layer portion of the well region. A gate insulating film is formed on the semiconductor layer and has a multilayer structure. A gate electrode is opposed to the channel region of the well region where a channel is formed through the gate insulating film.

A electronic device including a stack of a support substrate made of single-crystal SiC having a first surface and of a layer made of single-crystal SiC including a second surface opposite the first surface. The first surface corresponds to a plane of the SiC single crystal of the support substrate and the second surface corresponds to a plane inclined by at least 1° with respect to the plane of the SiC single crystal of the layer.

A device for manufacturing a SiC substrate, in which the occurrence of a work-affected layer is reduced, or from which a work-affected layer is removed, comprises: a main container which can accommodate a SiC substrate and which generates, by heating, a vapor pressure of a vapor-phase species including elemental Si and a vapor-phase species including elemental C in an internal space; and a heating furnace for accommodating the main container, generating a vapor pressure of the vapor-phase species including elemental Si in the internal space, and heating so that a temperature gradient is formed; the main container having an etching space formed by causing a portion of the main container disposed on the low-temperature side of the temperature gradient and the SiC substrate to face each other in a state in which the SiC substrate is disposed on the high-temperature side of the temperature gradient.

A surface activated bonding method by ion or atom bombardment of a first surface of a first substrate to a second surface of a second substrate, the material of the first substrate at the first surface including at least two chemical species, one of which, called the species of interest, becomes depleted upon activation by ion or atom bombardment, the method including depositing a layer of the species of interest onto the first surface of the first substrate; activating the first surface by bombarding the first surface with an ion or atom beam so as to consume the entire previously deposited layer of species; and activating the second surface by bombarding the second surface with an ion or atom beam; and contacting the first surface of the first substrate with the second surface of the second substrate.

A method includes providing a layer of porous silicon carbide supported by a silicon carbide substrate, providing a layer of epitaxial silicon carbide on the layer of porous silicon carbide, forming a plurality of semiconductor devices in the layer of epitaxial silicon carbide, and separating the substrate from the layer of epitaxial silicon carbide at the layer of porous silicon carbide. Additional methods are described.

A peeling layer is formed by applying a laser beam only to a central region of a workpiece other than a peripheral region extending inward from the peripheral edge of the workpiece by a predetermined distance. In this case, the application of the laser beam does not form the peeling layer in the peripheral region of the workpiece, and the formation of an ablation trace on the outer peripheral surface of the workpiece is prevented. As a result, it is possible to reduce a probability of occurrence of chipping in the peripheral region of a wafer peeled off from the workpiece when the wafer is subjected to a post-process.

A new substrate manufacturing method of obtaining a SiC epitaxial substrate having excellent flatness and a SiC epitaxial substrate having excellent flatness are provided. In a SiC epitaxial substrate having an epitaxial film obtained by epitaxially growing silicon carbide on a front surface of a silicon carbide substrate, the SiC epitaxial substrate has a first main surface made of the epitaxial film and a second main surface opposite to the first main surface. A maximum value of SBIR on the second main surface based on a 10 mm square site satisfies a condition of 0.1 .Math.m or more and 1.5 .Math.m or less.

Semiconductor devices comprising a getter material are described. The getter material can be located in or over the active region of the device and/or in or over a termination region of the device. The getter material can be a conductive or an insulating material. The getter material can be present as a continuous or discontinuous film. The device can be a SiC semiconductor device such as a SiC vertical MOSFET. Methods of making the devices are also described. Semiconductor devices and methods of making the same comprising source ohmic contacts formed using a self-aligned process are also described. The source ohmic contacts can comprise titanium silicide and/or titanium silicide carbide and can act as a getter material.

A bonding wafer structure includes a support substrate, a bonding layer, and a silicon carbide (SiC) layer. The bonding layer is formed on a surface of the support substrate, and the SiC layer is bonded onto the bonding layer, in which a carbon surface of the SiC layer is in direct contact with the bonding layer. The SiC layer has a basal plane dislocation (BPD) of 1,000 ea/cm.sup.2 to 20,000 ea/cm.sup.2, a total thickness variation (TTV) greater than that of the support substrate, and a diameter equal to or less than that of the support substrate. The bonding wafer structure has a TTV of less than 10 μm, a bow of less than 30 μm, and a warp of less than 60 μm.