Microsemi Corporation

Microchip Technology Inc.

Bruce Odekirk

Dumitru Sdrulla

Amaury Gendron-Hansen

Marc H Vandenberg

Cecil Kent Walters

Nathaniel C Berliner

Edward William Maxwell

Douglas C Thompson, Jr

Feng Zhao

Jacob Alexander Soto

Francis K Chai

A silicon carbide semiconductor device includes a silicon carbide (SiC) substrate having a SiC epitaxial layer disposed over a surface of the SiC substrate, the SiC substrate having a first conductivity and the SiC epitaxial layer having the first conductivity. A contact region and a well region are formed in the SiC epitaxial layer, the contact region and the well region have a doping level of a second conductivity opposite the first conductivity. The contact region lies completely within the well region, is not in contact with a region having the first conductivity and has edges recessed from edges of the well region.

Silicon carbide semiconductor device with a contact region having edges recessed from edges of the well region

A method for fabricating a silicon carbide semiconductor device includes providing a SiC epitaxial layer disposed over a surface of a SiC substrate, forming an implant aperture in a hardmask layer on a surface of the expitaxial SiC layer, implanting contact and well regions in the SiC epitaxial layer through the hardmask layer, the contact region lying completely within and recessed from edges of the well region by performing one of implanting the well region through the implant aperture, reducing the area of the implant aperture forming a reduced-area contact implant aperture and implanting the contact region through the reduced-area implant aperture to form a contact region, and implanting the contact region through the implant aperture, increasing the area of the implant aperture to form a increased-area well implant aperture and implanting the well region through the increased-area implant aperture to form a well region completely surrounding the contact region.

Self-aligned implants for silicon carbide (SiC) technologies and fabrication method

A silicon carbide semiconductor assembly and a method of forming a silicon carbide (SiC) semiconductor assembly are provided. The silicon carbide semiconductor assembly includes a semiconductor substrate and an electrode. The semiconductor substrate is formed of silicon carbide and includes a first surface, a second surface opposing the first surface, and a thickness extending therebetween. The method includes forming one or more electronic devices on the first surface and thinning the semiconductor substrate by removing the second surface to a predetermined depth of semiconductor substrate and leaving a third surface opposing the first surface. The method further includes forming a non-ohmic alloy layer on the third surface at a first temperature range and annealing the alloy layer at a second temperature range forming an ohmic layer, the second temperature range being greater than the first temperature range.

Method and assembly for ohmic contact in thinned silicon carbide devices

A semiconductor device constituted of: a semiconductor layer; and a field layer patterned on said semiconductor layer, said field layer constituted of material having characteristics which block diffusion of mobile ions and maintain structural integrity at activation temperatures of up to 1200 degrees centigrade.

Semiconductor device with improved field layer

A high power, high current Unidirectional Transient Voltage Suppressor, formed on SiC starting material is disclosed. The device is structured to avalanche uniformly across the entire central part (active area) such that very high currents can flow while the device is reversely biased. Forcing the device to avalanche uniformly across designated areas is achieved in different ways but consistently in concept, by creating high electric fields where the device is supposed to avalanche (namely the active area) and by relaxing the electric field across the edge of the structure (namely in the termination), which in all embodiments meets the conditions for an increased reliability under harsh environments.

SiC transient voltage suppressor

A Vertical Multiple Implanted Silicon Carbide Power MOSFET (VMIMOSFET) includes a first conductivity semiconductor substrate, a first conductivity semiconductor drift layer on the top of the substrate, a multitude of second conductivity layers implanted in the drift layer. The body layer is where the channel is formed. A first conductivity source layer is interspaced appropriately inside of the second conductivity layers. A gate oxide of a certain thickness and another oxide of a different thickness, a greater thickness than the gate oxide, placed in between the body layers but in such way that its shape does not distort the gate oxide in the channel. A charge compensated body layer of the second conductivity formed outside of the channel region and only at specific high electric field locations in the structure. The device and the manufacturing method deliver a power SiC MOSFET with increased frequency of operation and reduced switching losses.

Low loss SiC MOSFET

A vertical-sidewall dual-mesa static induction transistor (SIT) structure includes a silicon carbide substrate having a layer arrangement formed thereon. Laterally spaced ion implanted gate regions are defined in the layer arrangement. Source regions are defined in the layer arrangement. Each of the source regions can include a channel mesa having a source mesa disposed thereon. The source mesa includes upright sidewalls relative to a principal plane of the substrate defining a horizontal dimension thereof. The channel mesa includes upright sidewalls relative to the source mesa and the principal plane of the substrate. Also disclosed is a method of fabricating a vertical-sidewall dual-mesa SiC transistor device. The method includes implanting ions at an angle relative to a principal plane of the substrate to form gate junctions in upper portions of the substrate and lateral portions of the upright channel mesas.

Silicon carbide vertical-sidewall dual-mesa static induction transistor

A SiC Power Semiconductor device of the Field Effect Type (MOSFET, IGBT or the like) with 'muted' channel conduction, negative temperature coefficient of channel mobility, in situ 'ballasted' source resistors and optimized thermal management of the cells for increased Safe Operating Area is described. Controlling the location of the Zero Temperature Crossover Point (ZTCP) in relationship to the drain current is achieved by the partition between the &#x201c;active&#x201d; and &#x201c;inactive&#x201d; channels and by adjusting the mobility of the carriers in the channel for the temperature range of interest. The &#x201c;Thermal management&#x201d; is realized by surrounding the &#x201c;active&#x201d; cells/fingers with &#x201c;inactive&#x201d; ones and the &#x201c;negative&#x201d; feedback of the drain/collector current due to local increase of the gate bias is achieved by implementing in-situ &#x201c;ballast&#x201d; resistors inside of each source contact.

SiC power vertical DMOS with increased safe operating area

A merged PN/Schottky diode is provided having a substrate of a first conductivity type and a grid of doped wells of the second conductivity type embedded in the substrate. A Schottky barrier metal layer makes a Schottky barrier contact with the surface of the substrate above the grid. Selected embedded wells in the grid make a Schottky barrier contact to the Schottky barrier metal layer, while most embedded wells do not. The diode forward voltage drop is reduced for the same diode area with reverse blocking benefits similar to a conventional JBS structure.

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Bend, OR, United States of America

Bruce Odekirk