The characteristic of Fe-doped HEMTs is improved. The invention provides a nitride semiconductor substrate having a substrate, a buffer layer made of nitride semiconductors on the substrate, and an active layer composed of nitride semiconductor layers on the buffer layer; the buffer layer containing Fe, the Fe having a concentration profile in which the Fe concentration increases monotonically and gradually in the thickness direction of the buffer layer from an interface between the substrate and the buffer layer, has a maximum value within 210.sup.17 to 1.110.sup.20 atoms/cm.sup.3 inclusive, and decreases monotonically and gradually toward an interface between the buffer layer and the active layer, and the point of the maximum value being within 50 nm from the midpoint in the thickness direction of the buffer layer, and being 500 nm or more away from the interface between the buffer layer and the active layer.

Multiple wide bandgap semiconductor wafers, each having active circuitry and an epitaxially formed backside drain contact layer, may be constructed from a single bulk semiconductor substrate by: forming foundational layers on the top of the bulk substrate via epitaxy; forming active circuitry atop the foundational layers; laser treating the backside of the bulk substrate to create a cleave line in one of the foundational layers; and exfoliating a semiconductor wafer from the bulk substrate, where the exfoliated semiconductor wafer contains the active circuits and at least a portion of the foundational layers. Wafers containing the foundational layers without complete active devices may be produced in a similar manner. The foundational layers may comprise a drain contact layer and a drift layer, and may additionally include a buffer layer between the drain contact layer and the drift layer.

A multilayer composite bonding material for transient liquid phase bonding a semiconductor device to a metal substrate includes thermal stress compensation layers sandwiched between a pair of bonding layers. The thermal stress compensation layers may include a core layer with a first stiffness sandwiched between a pair of outer layers with a second stiffness that is different than the first stiffness such that a graded stiffness extends across a thickness of the thermal stress compensation layers. The thermal stress compensation layers have a melting point above a sintering temperature and the bonding layers have a melting point below the sintering temperature. The graded stiffness across the thickness of the thermal stress compensation layers compensates for thermal contraction mismatch between the semiconductor device and the metal substrate during cooling from the sintering temperature to ambient temperature.

The present invention provides a semiconductor device for reducing parasitic inductance.

The semiconductor device of the present invention includes: a semiconductor chip, including a front surface and a hack surface, and including a source pad. a drain pad and a gate pad on the front surface; a die pad, disposed under the semiconductor chip and bonded to the hack surface of the semiconductor chip; a source lead, electrically connected to the die pad; a drain lead and a gate lead, disposed on a periphery of the die pad; and a sealing resin, sealing the semiconductor chip, the die pad and each of the leads. At least one via for external connection is formed in the semiconductor chip to connect to the source pad, and the via for external connection is disposed on a circumferential portion of the semiconductor chip in perspective view.

A packaged semiconductor chip includes a power amplifier die including a semiconductor substrate, and an input contact pad, an output contact pad, first and second direct-current (DC) contact pads, one or more transistors having an input coupled to the input contact pad, and an input bias coupling path electrically coupling the first DC contact pad to the second DC contact pad and the input contact pad implemented on the semiconductor substrate. The chip further includes a lead frame having one or more radio-frequency input pins electrically coupled to the input contact pad, one or more radio-frequency output pins electrically coupled to the output contact pad, and first and second input bias pins electrically coupled to the first and second DC contact pads, respectively.

Multiple wide bandgap semiconductor wafers, each having active circuitry and an epitaxially formed backside drain contact layer, may be constructed from a single bulk semiconductor substrate by: forming foundational layers on the top of the bulk substrate via epitaxy; forming active circuitry atop the foundational layers; laser treating the backside of the bulk substrate to create a cleave line in one of the foundational layers; and exfoliating a semiconductor wafer from the bulk substrate, where the exfoliated semiconductor wafer contains the active circuits and at least a portion of the foundational layers. Wafers containing the foundational layers without complete active devices may be produced in a similar manner. The foundational layers may comprise a drain contact layer and a drift layer, and may additionally include a buffer layer between the drain contact layer and the drift layer.

An electronics assembly includes a semiconductor device having a first device surface and at least one device conductive layer disposed directly thereon. A cooling structure coupled to the semiconductor device includes a manifold layer, a microchannel layer bonded to the manifold layer, at least one planar side cooling structure, and one or more cooling structure conductive layers. The manifold layer includes a fluid inlet and a fluid outlet and defines a first cooling structure surface. The microchannel layer comprises at least one microchannel fluidly coupled to the fluid inlet and the fluid outlet and defines a second cooling structure surface opposite from the first cooling structure surface. The planar side cooling structure surface is transverse to the first and the second cooling structure surfaces. The cooling structure conductive layers are disposed directly on the first cooling structure surface, the second cooling structure surface, and the planar side cooling structure surface.

Multiple wide bandgap semiconductor wafers, each having active circuitry and an epitaxially formed backside drain contact layer, may be constructed from a single bulk semiconductor substrate by: forming foundational layers on the top of the bulk substrate via epitaxy; forming active circuitry atop the foundational layers; laser treating the backside of the bulk substrate to create a cleave line in one of the foundational layers; and exfoliating a semiconductor wafer from the bulk substrate, where the exfoliated semiconductor wafer contains the active circuits and at least a portion of the foundational layers. Wafers containing the foundational layers without complete active devices may be produced in a similar manner. The foundational layers may comprise a drain contact layer and a drift layer, and may additionally include a buffer layer between the drain contact layer and the drift layer.

An electronics assembly comprises a semiconductor device having a first device surface and at least one device conductive layer disposed on the first device surface. A cooling structure is coupled to the semiconductor device. The cooling structure comprises a first cooling structure surface and a second cooling structure surface. The second cooling structure surface is opposite from the first cooling structure surface and the first cooling structure surface is coupled to the semiconductor device. One side cooling structure surface is transverse to the respective first and second cooling structure surface. The one side electrode is disposed on the at least one side cooling structure surface in which the at least one side electrode is electrically coupled to the at least one device conductive layer. The cooling structure includes a fluid inlet for receiving a cooling fluid and a fluid outlet for removing the cooling fluid from the cooling structure.

A III-N enhancement-mode transistor includes a III-N structure including a conductive channel, source and drain contacts, and a gate electrode between the source and drain contacts. An insulator layer is over the III-N structure, with a recess formed through the insulator layer in a gate region of the transistor, with the gate electrode at least partially in the recess. The transistor further includes a field plate having a portion between the gate electrode and the drain contact, the field plate being electrically connected to the source contact. The gate electrode includes an extending portion that is outside the recess and extends towards the drain contact. The separation between the conductive channel and the extending portion of the gate electrode is greater than the separation between the conductive channel and the portion of the field plate that is between the gate electrode and the drain contact.