The subject matter disclosed herein relates to semiconductor power devices, such as silicon carbide (SiC) power devices. In particular, the subject matter disclosed herein relates to shielding regions in the form of channel region extensions for that reduce the electric field present between the well regions of neighboring device cells of a semiconductor device under reverse bias. The disclosed channel region extensions have the same conductivity-type as the channel region and extend outwardly from the channel region and into the JFET region of a first device cell such that a distance between the channel region extension and a region of a neighboring device cell having the same conductivity type is less than or equal to the parallel JFET width. The disclosed shielding regions enable superior performance relative to a conventional stripe device of comparable dimensions, while still providing similar reliability (e.g., long-term, high-temperature stability at reverse bias).

The subject matter disclosed herein relates to semiconductor power devices, such as silicon carbide (SiC) power devices. In particular, the subject matter disclosed herein relates to disconnected or connected shielding regions that reduce the electric field present between the well regions of neighboring device cells of a semiconductor device under reverse bias. The disclosed shielding regions occupy a widest portion of the JFET region between adjacent device cells such that a distance between a shielding region and well regions surrounding device cell is less than a parallel JFET width between two adjacent device cells, while maintaining a channel region width and/or a JFET region density that is greater than that of a comparable conventional stripe device. As such, the disclosed shielding regions and device layouts enable superior performance relative to a conventional stripe device of comparable dimensions, while still providing similar reliability (e.g., long-term, high-temperature stability at reverse bias).

The subject matter disclosed herein relates to silicon carbide (SiC) power devices. In particular, the present disclosure relates to shielding regions for use in combination with an optimization layer. The disclosed shielding regions reduce the electric field present between the well regions of neighboring device cells of a semiconductor device under reverse bias. The disclosed shielding regions occupy a portion of the JFET region between adjacent device cells and interrupt the continuity of the optimization layer in a widest portion of the JFET region, where the corners of neighboring device cells meet. The disclosed shielding regions and device layouts enable superior performance relative to a conventional stripe device of comparable dimensions, while still providing similar reliability (e.g., long-term, high-temperature stability at reverse bias).

Various improvements in vertical transistors, such as IGBTs, are disclosed. The improvements include forming periodic highly-doped p-type emitter dots in the top surface region of a growth substrate, followed by growing the various transistor layers, followed by grounding down the bottom surface of the substrate, followed by a wet etch of the bottom surface to expose the heavily doped p+ layer. A metal contact is then formed over the p+ layer. In another improvement, edge termination structures utilize p-dopants implanted in trenches to create deep p-regions for shaping the electric field, and shallow p-regions between the trenches for rapidly removing holes after turn-off. In another improvement, a dual buffer layer using an n-layer and distributed n+ regions improves breakdown voltage and saturation voltage. In another improvement, p-zones of different concentrations in a termination structure are formed by varying pitches of trenches. In another improvement, beveled saw streets increase breakdown voltage.

A device includes a semiconductor substrate, a buried doped isolation layer disposed in the semiconductor substrate to isolate the device, a drain region disposed in the semiconductor substrate and to which a voltage is applied during operation, and a depletion region disposed in the semiconductor substrate and having a conductivity type in common with the buried doped isolation barrier and the drain region. The depletion region reaches a depth in the semiconductor substrate to be in contact with the buried doped isolation layer. The depletion region establishes an electrical link between the buried doped isolation layer and the drain region such that the buried doped isolation layer is biased at a voltage level lower than the voltage applied to the drain region.

In one embodiment, a power MOSFET cell includes an N+ silicon substrate having a drain electrode. An N-type drift layer is grown over the substrate. An N-type layer, having a higher dopant concentration than the drift region, is then formed along with a trench having sidewalls. A P-well is formed in the N-type layer, and an N+ source region is formed in the P-well. A gate is formed over the P-well's lateral channel and has a vertical extension into the trench. A positive gate voltage inverts the lateral channel and increases the vertical conduction along the sidewalls to reduce on-resistance. A vertical shield field plate is also located next to the sidewalls and may be connected to the gate. The field plate laterally depletes the N-type layer when the device is off to increase the breakdown voltage. A buried layer and sinker enable the use of a topside drain electrode.

The semiconductor device of the present invention includes a first conductivity type semiconductor layer made of a wide bandgap semiconductor and a Schottky electrode formed to come into contact with a surface of the semiconductor layer, and has a threshold voltage V.sub.th of 0.3 V to 0.7 V and a leakage current J.sub.r of 110.sup.9 A/cm.sup.2 to 110.sup.4 A/cm.sup.2 in a rated voltage V.sub.R.

Apparatus and associated methods relate to an edge-termination structure surrounding a high-voltage MOSFET for reducing a peak lateral electric field. The edge-termination structure includes a sequence of annular trenches and semiconductor pillars circumscribing the high-voltage MOSFET. Each of the annular trenches is laterally separated from the other annular trenches by one of the semiconductor pillars. Each of the annular trenches has dielectric sidewalls and a dielectric bottom electrically isolating a conductive core within each of the annular trenches from a drain-biased region of the semiconductor pillar outside of and adjacent to the annular trench. The conductive core of the innermost trench is biased, while the conductive cores of one or more outer trenches are floating. In some embodiments, a surface of an inner semiconductor pillar is biased as well. The peak lateral electric field can advantageously be reduced by physical arrangement of trenches and electrical biasing sequence.

A semiconductor structure includes a silicon carbide layer, which has a unit region and a termination region surrounding the unit region. A first guard ring structure is located in the termination region of the silicon carbide layer, and adjoins a top surface of the silicon carbide layer. The first guard ring structure may include at least one first guard ring well region. A second guard ring structure is located in the silicon carbide layer and below the first guard ring structure. The second guard ring structure may include at least one second guard ring well region, which corresponds to the at least one first guard ring well region in a vertical direction. A method for manufacturing the semiconductor structure is also provided.

A semiconductor structure includes: a substrate, having a cell region and a terminal region, and having a first surface, a second located in the terminal region, and a third surface located in the cell region, the second surface and the third surface being located at different levels; a first trench structure, located in the cell region, traversing the third surface to extend towards the first surface, including a first semiconductor material layer and a first oxide layer partially protruding from the third surface, and extending in a first direction parallel to the third surface; and a second trench structure, located in the cell region, including a second semiconductor material layer and a second oxide layer partially protruding from the third surface, and extending parallel to the first direction, wherein the third surface is provided with a doped region between the first trench structure and the second trench structure.