A method of fabricating a semiconductor structure includes disposing a metal catalyst on a surface of a semiconductor. Thereafter, metal assisted chemical etching is performed, including holding the semiconductor immersed in an etchant solution and catalyzing an etching chemical reaction between the etchant solution and the semiconductor using the metal catalyst to etch the semiconductor to form a channel in the semiconductor. During at least a portion of the metal assisted chemical etching the semiconductor is held immersed in the etchant solution with a surface normal of the surface of the semiconductor at a non-zero angle respective to gravity. In some examples, an orientation of the semiconductor is changed during the metal assisted chemical etching to form the channel in the semiconductor with at least one bend or curved portion.

An electrostatic protection element including: a first impurity layer of second conductivity type formed on a semiconductor substrate of first conductivity type; a second impurity layer of the first conductivity type formed within the first impurity layer; a first contact layer of the first conductivity type formed in a region within the first impurity layer other than at the second impurity layer; a second and a third contact layer both of the second conductivity type and formed within the second impurity layer; and multilayer wiring connected through a stack structure to the first, the second, and the third contact layer, wherein the stack structure includes at least a first layer wiring connected to each of the first, the second, and the third contact layer, and a second layer wiring connected to the first layer wiring directly above each of the first, the second, and the third contact layer.

In one embodiment, a bi-directional punch-through semiconductor device can include: a first transistor in a first region of a semiconductor substrate of a first conductivity type, where the first transistor includes a semiconductor buried layer of a second conductivity type in the semiconductor substrate, and a first epitaxy region of an epitaxy semiconductor layer above the semiconductor buried layer, the semiconductor buried layer being configured as a base of the first transistor; and a second transistor coupled in parallel with the first transistor, where the second transistor is in a second region of the semiconductor substrate of the first conductivity type, where the second transistor comprises a second epitaxy region of the epitaxy semiconductor layer above the semiconductor substrate, and a first doped region of the second conductivity type in the second epitaxy region, the first doped region being configured as a base of the second transistor.

In one embodiment, a bi-directional punch-through semiconductor device can include: a first transistor in a first region of a semiconductor substrate of a first conductivity type, where the first transistor includes a semiconductor buried layer of a second conductivity type in the semiconductor substrate, and a first epitaxy region of an epitaxy semiconductor layer above the semiconductor buried layer, the semiconductor buried layer being configured as a base of the first transistor; and a second transistor coupled in parallel with the first transistor, where the second transistor is in a second region of the semiconductor substrate of the first conductivity type, where the second transistor comprises a second epitaxy region of the epitaxy semiconductor layer above the semiconductor substrate, and a first doped region of the second conductivity type in the second epitaxy region, the first doped region being configured as a base of the second transistor.

A low capacitance transient voltage suppressor with snapback control and a reduced voltage punch-through breakdown mode includes an n+ type substrate, a first epitaxial layer on the substrate, a buried layer formed within the first epitaxial layer, a second epitaxial layer on the first epitaxial layer, and an implant layer formed within the first epitaxial layer below the buried layer. The implant layer extends beyond the buried layer. A set of source regions is formed within a top surface of the second epitaxial layer. Implant regions are formed in the second epitaxial layer, with a first implant region located below the first source region.

In one embodiment, a bi-directional punch-through semiconductor device can include: a first transistor in a first region of a semiconductor substrate of a first conductivity type, where the first transistor includes a semiconductor buried layer of a second conductivity type in the semiconductor substrate, and a first epitaxy region of an epitaxy semiconductor layer above the semiconductor buried layer, the semiconductor buried layer being configured as a base of the first transistor; and a second transistor coupled in parallel with the first transistor, where the second transistor is in a second region of the semiconductor substrate of the first conductivity type, where the second transistor comprises a second epitaxy region of the epitaxy semiconductor layer above the semiconductor substrate, and a first doped region of the second conductivity type in the second epitaxy region, the first doped region being configured as a base of the second transistor.

A bidirectional Metal-Oxide-Semiconductor (MOS) device, including a P-type substrate, and an active region. The active region includes a drift region, a first MOS structure and a second MOS structure; the first MOS structure includes a first P-type body region, a first P+ contact region, a first N+ source region, a first metal electrode, and a first gate structure; the second MOS structure includes a second P-type body region, a second P+ contact region, a second N+ source region, a second metal electrode, and a second gate structure; and the drift region includes a dielectric slot, a first N-type layer, a second N-type layer, and an N-type region. The active region is disposed on the upper surface of the P-type substrate. The first MOS structure and the second MOS structure are symmetrically disposed on two ends of the upper layer of the drift region.

A bipolar junction transistor (BJT), which includes a collector layer, a base layer on the collector layer, an emitter layer on the base layer, and a recess region embedded in the collector layer, is disclosed. A base-collector plane is between the base layer and the collector layer. The recess region is may be below the base-collector plane. Further, the recess region and the base layer are a first type of semiconductor material. By embedding the recess region in the collector layer, the recess region and the collector layer form a first P-N junction, which may provide a point of avalanche for the BJT. Further, the collector layer and the base layer form a second P-N junction. By separating the point of avalanche from the second P-N junction, the BJT may avalanche robustly, thereby reducing the likelihood of avalanche induced failures, particularly in silicon carbide (SiC) BJTs.

A low capacitance transient voltage suppressor with snapback control and a reduced voltage punch-through breakdown mode includes an n+ type substrate, a first epitaxial layer on the substrate, a buried layer formed within the first epitaxial layer, a second epitaxial layer on the first epitaxial layer, and an implant layer formed within the first epitaxial layer below the buried layer. The implant layer extends beyond the buried layer. A first trench is at an edge of the buried layer and an edge of the implant layer. A second trench is at another edge of the buried layer and extends into the implant layer. A third trench is at another edge of the implant layer. A set of source regions is formed within a top surface of the second epitaxial layer. Implant regions are formed in the second epitaxial layer, with a first implant region located below the first source region.

The present application relates to a turn-off power semiconductor device having a wafer with an active region and a termination region surrounding the active region, a rubber ring as an edge passivation for the wafer and a gate ring placed on a ring-shaped gate contact on the termination region for contacting the gate electrodes of a thyristor cell formed in the active region of the wafer. In the turn-off power semiconductor device, the outer circumferential surface of the gate ring is in contact with the rubber ring to define the inner border of the rubber ring. The area consumed by the ring-shaped gate contact on the termination or edge region can be minimized. The upper surface of the gate ring and the upper surface of the rubber ring form a continuous surface extending in a plane parallel to the first main side of the wafer.