The present invention provides a switching device (100) for power conversion in which a first gate electrode (6), a p-type channel layer (2) having an n-type emitter region (3), a second gate electrode (13), and a p-type floating layer (15) are repeatedly arranged in order on the surface side of an n-type semiconductor substrate (1). An interval a between the two gates (6, 13) that sandwich the p-type channel layer (2) is configured to be smaller than an interval b between the two gates (13, 6) that sandwich the p-type floating layer (15). The first gate electrode (6) and the second gate electrode (13) are both supplied with drive signals having a time difference in drive timing.

The betas of the bipolar transistors in a BiCMOS semiconductor structure are increased by forming the emitters of the bipolar transistors with two implants: a source-drain implant that forms a first emitter region at the same time that the source and drain regions are formed, and an additional implant that forms a second emitter region at the same time that another region is formed. The additional implant has an implant energy that is greater than the implant energy of the source-drain implant.

A graphene base transistor comprises on a semiconductor substrate surface an emitter pillar and an emitter-contact pillar, which extend from a pillar foundation in a vertical direction. A dielectric filling layer laterally embeds the emitter pillar and the emitter-contact pillar above the pillar foundation. The dielectric filling layer has an upper surface that is flush with a top surface of the emitter pillar and with the at least one base-contact arm of a base-contact structure. A graphene base forms a contiguous layer between a top surface of the emitter pillar and a top surface of the base-contact arm. A collector stack and the base have the same lateral extension parallel to the substrate surface and perpendicular to those edges of the top surface of the emitter pillar and the base-contact arm that face each other.

An IGBT includes a floating P well, and a floating N+ well that extends down into the floating P well. A bottom surface of the floating P well has a waved contour so that it has thinner portions and thicker portions. When the device is on, electrons flow laterally from an N+ emitter, and through a first channel region. Some electrons pass downward, but others pass laterally through the floating N+ well to a local bipolar transistor located at a thinner portion of the floating P type well. The transistor injects electrons down into the N drift layer. Other electrons pass farther through the floating N+ well, through the second channel region, and to an electron injector portion of the N drift layer. The extra electron injection afforded by the floating well structures reduces V.sub.CE(SAT). The waved contour is made without adding any masking step to the IGBT manufacturing process.

A heterojunction bipolar transistor (HBT) amplifier device includes transistor fingers arranged in parallel on a substrate. Each transistor finger includes a base/collector mesa stripe shaving a trapezoidal shaped cross-section with sloping sides, and having a base stacked on a collector; a set of emitter mesa stripes arranged on the base/collector mesa stripe; and emitter metallization formed over the set of emitter mesa stripes and the base/collector mesa. The emitter metallization includes a center portion for providing electrical and thermal connectivity to the emitter mesa stripes and extended portions extending beyond the base and overlapping onto the sloping sides of the base/collector mesa stripe for increasing thermal coupling to the collector. A common conductive pillar is formed over the transistor fingers for providing electrical and thermal conductivity. Also, thermal shunts are disposed on the substrate between adjacent transistor fingers, where the thermal shunts are electrically isolated from the transistor fingers.

A voltage-controlled switching device includes a drain/drift structure formed in a semiconductor portion with a lateral cross-sectional area A.sub.Q, a source/emitter terminal, and an emitter channel region between the drain/drift structure and the source/emitter terminal. A resistive path electrically connects the source/emitter terminal and the emitter channel region. The resistive path has an electrical resistance of at least 0.1 m*cm.sup.2/A.sub.Q.

An object is to provide a technique that can reduce energy loss during the transient On-period. A semiconductor device includes a first transistor, a second transistor, and a controller. The controller is configured to, before the first transistor enters a transient Off-state, apply a second Off-voltage lower than a first Off-voltage to the second gate, before the first transistor enters a transient On-state, turn On the second transistor, and after the first transistor is turned On, apply the first Off-voltage to the second gate to turn Off the second transistor.

The present disclosure relates to semiconductor structures and, more particularly, to bipolar transistors and methods of manufacture. The structure includes: a collector; a base region above the collector; an emitter laterally connecting to the base region; and an extrinsic base connecting to the base region.

Semiconductor devices and corresponding methods of manufacture are disclosed. The method includes forming vertical channel structures on a substrate. The vertical channel structures are formed within a layer stack of alternating layers of a first metal and a first dielectric. The vertical channel structures are channels of field effect transistors that have a current flow path perpendicular to a surface of the substrate. The vertical channel structures have a dielectric core. The method includes forming openings on the substrate that uncover a region of the layer stack adjacent to the vertical channel structures. The method includes, for each vertical channel structure, forming a corresponding staircase region in the layer stack, and forming metal contacts within each staircase region.

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 semiconductor devices in the layer of epitaxial silicon carbide; and separating the silicon carbide substrate from the layer of epitaxial silicon carbide at the layer of porous silicon carbide. The layer of porous silicon carbide includes dopants defining a resistivity of the layer of porous silicon carbide. The resistivity of the layer of porous silicon carbide is different from a resistivity of the silicon carbide substrate. Additional methods are described.