Abb Research Ltd.

Acreo Ab

Abb Reasearch Ltd.

Cree Gmbh

Mietek Bakowski

Ulf Gustafsson

Christopher Ian Harris

Kurt Rottner

Lennart Zdansky

Bo Bijlenga

Susan Savage

Adolf Schoner

Mats Andersson

Heinz Lendenmann

Willy Hermansson

Lennart Kruse

Andrey Konstantinov

Lennart Ramberg

Fanny Dahlquist

Nils Lundberg

Mikael Ostling

Bo Breitholtz

Henry Bleichner

Jan Szmidt

Harry Bleichner

Ulf Gustavsson

A semiconductor device comprises at least one first semiconductor layer ( ) and a second layer ( ) applied on at least a surface portion of the first layer for protecting the device. The protecting layer is of a second material having a larger energy gap between the valence band and the conduction band than a first material forming said first layer. The second material has at least in one portion of said protecting layer a nano-crystalline and amorphous structure by being composed of crystalline gains with a size less than 100 nm and a resistivity at room temperature exceeding 1&times;10 &OHgr;cm.

Protective layer for a semiconductor device

A semiconductor device of planar structure has a pn-junction ( ) formed by a first layer ( ) doped according to a first conductivity type, n or p, and on top thereof a second layer ( ) doped according to a second conductivity type. The second layer has a higher doping concentration than the first layer and a lateral edge thereof is provided with an edge termination with second zones of said second conductivity type separated by first zones ( ) of said first conductivity type arranged so that the total charge and/or the effective sheet charge density of dopants according to said second conductivity type is decreasing towards the laterally outer border ( ) of the edge termination. A third layer ( ) doped according to said first conductivity type is arranged on top of said second layer at least in the region of the edge termination for burying the edge termination of the device thereunder.

Semiconductor device and a method for production thereof

A bipolar transistor having at least a low doped drift layer (,) of crystalline SiC comprises at least one first layer (,) of a semi-conductor material having a wider energy gap between the conduction band and the valence band than an adjacent layer (,) of SiC.

Bipolar transistor having a low doped drift layer of crystalline SiC

A transistor of SiC for high voltage and high switching frequency applications is a MISFET or an IGBT. This transistor comprises a plurality of laterally spaced active regions. The center to center distance of two adjacent active regions defines a lateral width of a cell of the transistor. The relation of the lateral width of an accumulation region defined as the region in the drift layer connecting to a gate-insulating layer in each individual cell and the lateral cell width is selected so as to keep the power losses in the transistor as a consequence of switching below a determined proportion to the power losses relating to conduction of the transistor for a predetermined switching frequency and on-state voltage for which the transistor is designed.

Transistor of SIC

A transistor of SiC having a drain and a highly doped substrate layer is formed on the drain. A highly n type buffer layer may optionally be formed on the substrate layer. A low doped n-type drift layer, a p-type base layer, a high doped n-type source region layer and a source are formed on the substrate layer. An insulating layer with a gate electrode is arranged on top of the base layer and extends substantially laterally from at least the source region layer to a n-type layer. When a voltage is applied to the gate electrode, a conducting inversion channel is formed extending substantially laterally in the base layer at an interface of the p-type base layer and the insulating layer. The p-type base layer is low doped in a region next to the interface to the insulating layer at which the inversion channel is formed and highly doped in a region thereunder next to the drift layer.

Semiconductor device having high channel mobility and a high breakdown

A Schottky diode of SiC has a substrate layer, a drift layer and emitter layer regions formed in the drift layer. A metal layer makes an ohmic contact to the emitter layer regions and Schottky contact to the drift layer. A depletion of the drift layer region between two adjacent emitter layer regions is allowed in the blocking state of the diode making the two adjacent p-type emitter layer regions form a continuous depleted region therebetween in this state.

Schottky diode of SiC and a method for production thereof

A semiconductor device of SiC is adapted to hold high voltages in the blocking state thereof. The device comprises two parts (1, 2) each comprising one or more semiconductor layers of SiC and connected in series between two opposite terminals of the device, namely a sub-semiconductor device (1) able to withstand only low voltages in the blocking state thereof and a voltage-limiting part (2) able to withstand high voltages in the blocking state of the device and adapted to protect said sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof.

Semiconductor device of SiC having an insulated gate and buried grid

A semiconductor component and a method for processing said component, which comprises a pn junction, where both the p-conducting (3) and the n-conducting layers (2) of the pn junction constitute doped silicon carbide layers and where the edge of the higher doped conducting layer of the pn junction exhibits a charge profile with a stepwise or uniformly decreasing total charge or effective surface charge density from the initial value at the main pn junction to a zero or almost zero total charge or charge density at the outermost edge of the junction following a radial direction from the central part of the junction towards the outermost edge.

Fabrication of a SiC semiconductor device comprising a pn junction with

A semiconductor component including a silicon carbide substrate. A pn junction includes doped layers of the substrate. The pn junction includes at a surface of the substrate a low doped first conductivity type layer and at a portion of the surface of the substrate a highly doped second conductivity type layer. An edge termination region of the pn junction laterally surrounds the pn junction provided at an edge of at least one of the layers of the pn junction. The edge termination region includes zones of the second conductivity type located at an edge of the highly doped second conductivity type layer. A charge content of the zones decreases toward an edge of the edge termination region in accordance with at least one characteristic selected from the group consisting of a stepwise or continuously decreasing total charge towards an outer border of the edge termination region and a decreasing effective sheet charge density toward an outer border of the edge termination region. An outermost zone of the edge termination region is completely depleted at full design voltage.

SiC semiconductor device comprising a pn junction with a voltage

A semiconductor device of planar structure, comprises a pn junction, formed of a first type conducting layer and on top thereof a second type conducting layer, both layers of doped silicon carbide, the edge of the second of the layers being provided with an edge termination (JTE), enclosing stepwise or continuously decreasing effective sheet charge density towards the outer border of the termination, wherein the pn junction and its JTE are covered by a doped or undoped SiC third layer.

SiC semiconductor device comprising a pn junction

A field controlled semiconductor device of SiC comprises superimposed in the order mentioned at least a drain (12), a highly doped substrate layer (1) and a low doped n-type drift layer (2). It has also a highly doped n-type source region layer (6) and a source (11) connected thereto. A doped channel region layer (4) connects the source region layer to the drift layer, and a current is intended to flow therethrough when the device is in an on-state. The device has also a gate electrode (9). The channel region layer has a substantially lateral extension and is formed by a low doped n-type layer (4). The gate electrode (9) is arranged to influence the channel region layer from above for giving a conducting channel (17) created therein from the source region layer to the drift layer a substantially lateral extension.

Field controlled semiconductor device of SiC and a method for production

A semiconductor diode structure with a Schottky junction, wherein a metal contact and a silicon carbide semiconductor layer of a first conducting type form the junction and wherein the edge of the junction exhibits a junction termination divided into a transition belt (TB) having gradually increasing total charge or effective sheet charge density closest to the metal contact and a Junction Termination Extension (JTE) outside the transition belt, the JTE having a charge profile with a stepwise or uniformly deceasing total charge or effective sheet charge density from an initial value to a zero or almost zero total charge at the outermost edge of the termination following a radial direction from the center part of the JTE towards the outermost edge of the termination. The purpose of the transition belt is to reduce the electric field concentration at the edge of the metal contact of the Schottky diode, while the purpose of the junction termination extension is to control the electric field at the periphery of the diode.

Junction termination for SiC Schottky diode

An IGBT comprises a drain, a highly doped p-type substrate layer, a highly doped n-type buffer layer, a drift layer, a p-type base layer, a highly doped n-type source region layer and a source electrode. A trench is etched in the base layer and an insulating layer with a gate electrode thereon is arranged on the base layer from the source region layer to the drift layer for the creation of a conducting inversion channel there. A contact portion is provided vertically separated from the source region layer and has the source electrode applied thereon for collecting holes injected from the substrate layer to the drift layer at a vertical distance from the source region layer.

Insulated gate bipolar transistor having a trench

A pn-diode of SiC has a first emitter layer part doped with first dopants having a low ionization energy and a second part designed as a grid and having portions extending vertically from above and past the junction between the drift layer and the first part and being laterally separated from each other by drift layer regions for forming a pn-junction by the first part and the drift layer adjacent such portions at a vertical distance from a lower end of the grid portions. The different parameters of the device are selected to allow a depletion of the drift layer in the blocking state form a continuous depleted region between the grid portions, to thereby screen off the high electric field at the pn-junction so that it will not be exposed to high electrical fields.

PN-diode of SiC and a method for production thereof

A bipolar semiconductor comprising layers of SiC semiconductor material. At least one pn-junction is formed between two of the layers having charged carrier transport across the junction when the device is in a conductive state. A resistive element in series with the pn-junction lowers the current through the pn-junction as the voltage drop across the device increases with an increase in temperature. The temperature coefficient for the device switches from a negative to a positive at a lower current through the device.

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Mietek Bakowski