Abstract: There is disclosed the integration of a Schottky diode with a MOSFET, more in detail there is a free-wheeling Schottky diode and a power MOSFET on top of a buried grid material structure. Advantages of the specific design allow the whole surface area to be used for MOSFET and Schottky diode structures, the shared drift layer is not limited by Schottky diode or MOSFET design rules and therefore, one can decrease the thickness and increase the doping concentration of the drift layer closer to a punch through design compared to the state of the art. This results in higher conductivity and lower on-resistance of the device with no influence on the voltage blocking performance. The integrated device can operate at higher frequency. The risk for bipolar degradation is avoided.

Abstract: An example apparatus includes a semiconductor wafer with a plurality of probe pads each formed centered in scribe streets and intersected by saw kerf lanes. Each probe pad includes a plurality of lower level conductor layers arranged in lower level conductor frames, a plurality of lower level vias extending vertically through lower level insulator layers and electrically coupling the lower level conductor frames; a plurality of upper level conductor layers, each forming two portions on two outer edges of the probe pad, the two portions aligned with, spaced from, and on opposite sides of the saw kerf lane, the coverage of the upper level conductor layers being less than about twenty percent; and a plurality of upper level vias extending vertically through upper level insulator layers and coupling the upper level conductor layers electrically to one another and to the lower level conductor layers. Methods are disclosed.

Abstract: A semiconductor device includes a substrate having a first conductivity type, a high-voltage well having a second conductivity type and disposed in the substrate, a high-voltage doped region having the first conductivity type and disposed in the high-voltage well, a drain region disposed in the high-voltage well and spaced apart from the high-voltage doped region, a source region disposed in the high-voltage doped region, a first gate structure disposed above a first side portion of the high-voltage doped region between the source region and the drain region, and a second gate structure disposed above a second and opposite side portion of the high-voltage doped region.

Abstract: There are provided a semiconductor device and a method of manufacturing the same. The semiconductor device includes a body layer of a first conductivity type; an active layer of a second conductivity type, contacting an upper portion of the body layer; and a field limiting ring of a first conductivity type, formed in an upper portion of the active layer.

Abstract: A MOSFET device and fabrication method are disclosed. The MOSFET has a drain in chip plane with an epitaxial layer overlay atop. The MOSFET further comprises: a Kelvin-contact body and an embedded Kelvin-contact source; a trench gate extending into the epitaxial layer; a lower contact trench extending through the Kelvin-contact source and at least part of the Kelvin-contact body defining respectively a vertical source-contact surface and a vertical body-contact surface; a patterned dielectric layer atop the Kelvin-contact source and the trench gate; a patterned top metal layer. As a result: a planar ledge is formed atop the Kelvin-contact source; the MOSFET device exhibits a lowered body Kelvin contact impedance and, owing to the presence of the planar ledge, a source Kelvin contact impedance that is lower than an otherwise MOSFET device without the planar ledge; and an integral parallel Schottky diode is also formed.

Abstract: A semiconductor structure includes a III-nitride substrate characterized by a first conductivity type and having a first side and a second side opposing the first side, a III-nitride epitaxial layer of the first conductivity type coupled to the first side of the III-nitride substrate, and a plurality of III-nitride epitaxial structures of a second conductivity type coupled to the III-nitride epitaxial layer. The semiconductor structure further includes a III-nitride epitaxial formation of the first conductivity type coupled to the plurality of III-nitride epitaxial structures, and a metallic structure forming a Schottky contact with the III-nitride epitaxial formation and coupled to at least one of the plurality of III-nitride epitaxial structures.

Abstract: A guard ring for a through via, and a method of manufacture thereof, is provided. The guard ring comprises one or more rings around a through via, wherein the rings may be, for example, circular, rectangular, octagon, elliptical, square, or the like. The guard ring may be formed from a contact through an inter-layer dielectric layer and interconnect structures (e.g., vias and lines) extending through the inter-metal dielectric layers. The guard ring may contact a well formed in the substrate.

Abstract: According to one embodiment, a semiconductor device includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a first conductivity type, a third semiconductor layer of a second conductivity type, an isolation layer, and a guard ring layer of the second conductivity type. The second semiconductor layer is provided on the first semiconductor layer. The third semiconductor layer is provided on the second semiconductor layer to be joined to the second semiconductor layer. The isolation layer surrounds a periphery of the third semiconductor layer and is deeper than the third semiconductor layer. The guard ring layer is provided between the third semiconductor layer and the isolation layer, adjacent to the third semiconductor layer, and deeper than the third semiconductor layer.

Abstract: An electrostatic discharge (ESD) protection circuit structure includes several diffusion regions and a MOS transistor. The circuit structure includes a first diffusion region of a first type (e.g., P-type or N-type) formed in a first well of the first type, a second diffusion region of the first type formed in the first well of the first type, and a first diffusion region of a second type (e.g., N-type or P-type) formed in a first well of the second type. The first well of the second type is formed in the first well of the first type. The MOS transistor is of the second type and includes a drain formed by a second diffusion region of the second type formed in a second well of the second type bordering the first well of the first type.

Abstract: A semiconductor device including a cell region and a peripheral region, the semiconductor device comprising: a guard ring region provided between the cell region and the peripheral region, the guard ring region having a barrier structure.

Abstract: A semiconductor device is disclosed wherein a peripheral region with a high breakdown voltage and high robustness against induced surface charge is manufactured using a process with high mass productivity. The device has n-type drift region and p-type partition region of layer-shape deposited in a vertical direction to one main surface of n-type semiconductor substrate with high impurity concentration form as drift layer, alternately adjacent parallel pn layers in a direction along one main surface. Active region through which current flows and peripheral region enclosing the active region include parallel pn layers.

Abstract: A seal ring structure is formed through a multilayer structure of a plurality of dielectric films in a peripheral part of a chip region to surround the chip region. A dual damascene interconnect in which an interconnect and a plug connected to the interconnect are integrated is formed in at least one of the dielectric films in the chip region. Part of the seal ring structure formed in the dielectric film in which the dual damascene interconnect is formed is continuous. A protection film formed on the multilayer structure has an opening on the seal ring. A cap layer connected to the seal ring is formed in the opening.

Abstract: Structures and methods are provided for nanosecond electrical pulse anneal processes. The method of forming an electrostatic discharge (ESD) N+/P+ structure includes forming an N+ diffusion on a substrate and a P+ diffusion on the substrate. The P+ diffusion is in electrical contact with the N+ diffusion. The method further includes forming a device between the N+ diffusion and the P+ diffusion. A method of annealing a structure or material includes applying an electrical pulse across an electrostatic discharge (ESD) N+/P+ structure for a plurality of nanoseconds.

Abstract: Provided is a power semiconductor device including a guard ring region to protect control devices. The power semiconductor device includes a semiconductor body layer extending over a semiconductor substrate of a first conductivity type. The semiconductor body layer has a second conductivity type opposite the first conductivity type. A well of the first conductivity type extends in the semiconductor body layer and is configured to be electrically insulated from the semiconductor substrate. At least one control device is formed in the well, where the control device comprises at least one of PN junction. A guard ring region of the first conductivity type is laterally spaced from but surrounds the well. The guard ring region together with the semiconductor substrate and the semiconductor body layer form a parasitic bipolar transistor, and the guard ring region functions as a collector of the parasitic bipolar transistor.

Abstract: A seal ring structure is formed through a multilayer structure of a plurality of dielectric films in a peripheral part of a chip region to surround the chip region. A dual damascene interconnect in which an interconnect and a plug connected to the interconnect are integrated is formed in at least one of the dielectric films in the chip region. Part of the seal ring structure formed in the dielectric film in which the dual damascene interconnect is formed is continuous. A protection film formed on the multilayer structure has an opening on the seal ring. A cap layer connected to the seal ring is formed in the opening.

Abstract: An ESD protection circuit includes a MOS transistor of a first type, a MOS transistor of a second type, an I/O pad, and first, second, and third guard rings of the first, second, and first types, respectively. The MOS transistor of the first type has a source coupled to a first node having a first voltage, and a drain coupled to a second node. The MOS transistor of the second type has a drain coupled to the second node, and a source coupled to a third node having a second voltage lower than the first voltage. The I/O pad is coupled to the second node. The first, second, and third guard rings are positioned around the MOS transistor of the second type.

Abstract: The present invention provides a lateral diffused metal-oxide-semiconductor device including a first doped region, a second doped region, a third doped region, a gate structure, and a contact metal. The first doped region and the third doped region have a first conductive type, and the second doped region has a second conductive type. The second doped region, which has a racetrack-shaped layout, is disposed in the first doped region, and has a long axis. The third doped region is disposed in the second doped region. The gate structure is disposed on the first doped region and the second doped region at a side of the third doped region. The contact metal is disposed on the first doped region at a side of the second doped region extending out along the long axis, and is in contact with the first doped region.

Abstract: A laterally diffused metal oxide semiconductor transistor. The laterally diffused metal oxide semiconductor transistor includes a substrate, a drain formed thereon, a source formed on the substrate, comprising a plurality of individual sub-sources respectively corresponding to various sides of the drain, a plurality of channels formed in the substrate between the sub-sources and the drain, a gate overlying a portion of the sub-sources and the channels, and a drift layer formed in the substrate underneath the drain.

Abstract: A super-junction trench MOSFET is disclosed for high voltage device by applying a first doped column region of first conductivity type between a pair of second doped column regions of second conductivity type adjacent to sidewalls of a pair of deep trenches with buried voids in each unit cell for super-junction. Meanwhile, at least one trenched gate and multiple trenched source-body contacts are formed in each unit cell between the pair of deep trenches.

Abstract: A super-junction trench MOSEET is disclosed for high voltage device by applying a first doped column region of first conductivity type between a pair of second doped column regions of second conductivity type adjacent to sidewalls of a pair of deep trenches in each unit cell for super-junction. Meanwhile, at least one trenched gate and multiple trenched source-body contacts are formed in each unit cell between the pair of deep trenches.

Abstract: A semiconductor layer has a second impurity concentration. First trenches are formed in the semiconductor layer to extend downward from an upper surface of the semiconductor layer. Each of insulation layers is formed along each of the inner walls of the first trenches. Each of conductive layers is formed to bury each of the first trenches via each of the insulation layers, and extends downward from the upper surface of the semiconductor layer to a first position. A first semiconductor diffusion layer reaches a second position from the upper surface of the semiconductor layer, is positioned between the first trenches, and has a third impurity concentration lower than the second impurity concentration. A length from the upper surface of the semiconductor layer to the second position is equal to or less than half a length from the upper surface of the semiconductor layer to the first position.

Abstract: A switching transistor includes a substrate having a substrate dopant concentration and a barrier region bordering on the substrate, having a first conductivity type and having a barrier region dopant concentration that is higher than the substrate dopant concentration. A source region is embedded in the barrier region, and has a second conductivity type and has a dopant concentration that is higher than the barrier region dopant concentration. A drain region is embedded in the barrier region and is offset from the source region. The draining region has the second conductivity type and a dopant concentration that is higher than the barrier region dopant concentration. A channel region extends between the source region and the drain region, wherein the channel region comprises a subregion of the barrier region. An insulation region covers the channel region and is disposed between the channel region and a gate electrode.

Abstract: A seal ring structure is formed through a multilayer structure of a plurality of dielectric films in a peripheral part of a chip region to surround the chip region. A dual damascene interconnect in which an interconnect and a plug connected to the interconnect are integrated is formed in at least one of the dielectric films in the chip region. Part of the seal ring structure formed in the dielectric film in which the dual damascene interconnect is formed is continuous. A protection film formed on the multilayer structure has an opening on the seal ring. A cap layer connected to the seal ring is formed in the opening.

Abstract: This invention discloses a semiconductor power device that includes an active cell area having a plurality of power transistor cells. Each of said power transistor cells has a planar Schottky diode that includes a Schottky junction barrier metal covering areas above gaps between separated body regions between two adjacent power transistor cells. The separated body regions further provide a function of adjusting a leakage current of said Schottky diode in each of said power transistor cells. Each of the planar Schottky diodes further includes a Shannon implant region disposed in a gap between the separated body regions of two adjacent power transistor cells for further adjusting a leakage current of said Schottky diode. Each of the power transistor cells further includes heavy body doped regions in the separated body regions next to source regions surrounding said Schottky diode forming a junction barrier Schottky (JBS) pocket region.

Abstract: One embodiment of an integrated circuit includes a semiconductor body. In the semiconductor body a first trench region extends into the semiconductor body from a first surface. The integrated circuit further includes a diode including an anode region and a cathode region. One of the anode region and the cathode region is at least partly arranged in the first trench region. The other one of the anode region and the cathode region includes a first semiconductor region adjoining the one of the anode region and the cathode region from outside of the first trench region.

Abstract: A semiconductor device includes a semiconductor substrate of a first conductivity type, including a first main surface and a second main surface opposite to each other. A power semiconductor element includes a first electrode in a first region at the first main surface of the semiconductor substrate, and a second electrode at the second main surface. A current flows between the first electrode and the second electrode. The semiconductor device also includes a guard ring of a second conductivity type, in a second region at the first main surface, at a more outer circumference than the first region. A semi-insulating insulation film covers the second region. A dielectric film in the second region covers the semi-insulating insulation film. A flow block portion in a third region at the first main surface, at a more outer circumference than the second region, prevents a flow out of the dielectric film.

Abstract: A method for manufacturing a Schottky diode comprising steps of 1) providing a region with a dopant of a second conductivity type opposite to a first conductivity type to form a top doped region in a semiconductor substrate of said first conductivity type; 2) providing a trench through the top doped region to a predetermined depth and providing a dopant of the second conductivity type to form a bottom dopant region of the second conductivity type; and 3) lining a Schottky barrier metal layer on a sidewall of the trench at least extending from a bottom of the top doped region to a top of the bottom doped region.

Abstract: One embodiment of the invention relates to an unguarded Schottky barrier diode. The diode includes a cathode that has a recessed region and a dielectric interface surface that laterally extends around a perimeter of the recessed region. The diode further includes an anode that conforms to the recessed region. A dielectric layer extends over the dielectric interface surface of the cathode and further extends over a portion of the anode near the perimeter. Other devices and methods are also disclosed.

Abstract: A semiconductor device including a semiconductor substrate having a first conductive type layer; a first diffusion region which has the first conductive type and is formed in the first conductive type layer; a second diffusion region which has a second conductive type and an area larger than an area of the first diffusion region and overlaps the first diffusion region; and a PN junction formed at an interface between the first and the second diffusion regions. The second diffusion region includes a ring shaped structure or a guard ring includes an inverted region which has the second conductive type. According to such a configuration, it is possible to provide a semiconductor device having the required Zener characteristics with good controllability.

Abstract: A semiconductor junction barrier Schottky (JBS-SKY) diode with enforced upper contact structure (EUCS) is disclosed. Referencing an X-Y-Z coordinate, the JBS-SKY diode has semiconductor substrate (SCST) parallel to X-Y plane. Active device zone (ACDZ) atop SCST and having a JBS-SKY diode with Z-direction current flow. Peripheral guarding zone (PRGZ) atop SCST and surrounding the ACDZ. The ACDZ has active lower semiconductor structure (ALSS) and enforced active upper contact structure (EUCS) atop ALSS. The EUC has top contact metal (TPCM) extending downwards and in electrical conduction with bottom of EUCS; and embedded bottom supporting structure (EBSS) inside TPCM and made of a hard material, the EBSS extending downwards till bottom of the EUCS. Upon encountering bonding force onto TPCM during packaging of the JBS-SKY diode, the EBSS enforces the EUCS against an otherwise potential micro cracking of the TPCM degrading the leakage current of the JBS-SKY diode.

Abstract: A power semiconductor component having a pn junction, a body with a first basic conductivity, a well-like region with a second conductivity which is arranged horizontally centrally in the body, has a first two-level doping profile and has a first penetration depth from the first main surface into the body. In addition, this power semiconductor component has an edge structure which is arranged between the well-like region and the edge of the power semiconductor component and which comprises a plurality of field rings with a single-level doping profile, a second conductivity and a second penetration depth, wherein the first penetration depth is no more than about 50% of the second penetration depth.

Abstract: A method for forming a semiconductor structure includes forming a plurality of fuses over a semiconductor substrate; forming a plurality of interconnect layers over the semiconductor substrate and a plurality of interconnect pads at a top surface of the plurality of interconnect layers; and forming a seal ring, wherein the seal ring surrounds active circuitry formed in and on the semiconductor substrate, the plurality of interconnect pads, and the plurality of fuses, wherein each fuse of the plurality of fuses is electrically connected to a corresponding interconnect pad of the plurality of interconnect pads and the seal ring, and wherein when each fuse of the plurality of fuses is in a conductive state, the fuse electrically connects the corresponding interconnect pad to the seal ring.

Abstract: The semiconductor memory device has a fuse area in which fuse elements for registering addresses of defective memory cells are arranged. A guard ring is formed around the fuse area and is covered by a passivation film. The passivation film above the fuse area has an opening. The guard ring has a first ring in a first layer, a second ring in a second layer and a third ring in a third layer. These rings are connected by a first connecting ring and a second connecting ring. The first ring is positioned at an inward part of the second ring to provide an area unoccupied by the first ring beneath the second ring.

Abstract: A semiconductor device in one embodiment includes a depletion junction, a peripheral region adjacent the depletion junction, and a buffer layer. The buffer layer is adapted to reduce localization of avalanche breakdown proximate the interface between the depletion junction and the peripheral region.

Abstract: A “tabbed” MOS device provides radiation hardness while supporting reduced gate width requirements. The “tabbed” MOS device also utilizes a body tie ring, which reduces field threshold leakage. In one implementation the “tabbed” MOS device is designed such that a width of the tab is based on at least a channel length of the MOS device such that a radiation-induced parasitic conduction path between the source and drain region of the device has a resistance that is higher than the device channel resistance.

Abstract: A semiconductor device in which a first insulated gate field effect transistor (1) is connected in series with a second field effect transistor, FET, (2), wherein the second field effect transistor (2) has a heavily doped source region (19A) which is electrically connected to a heavily doped drain contact region (191) of the first insulated gate field effect transistor, and further that the breakthrough voltage of the first insulated gate field effect transistor (1) is higher than the pinch voltage, Vp, of the second field effect transistor (2).

Abstract: A Schottky diode comprises an ohmic layer that can serve as a cathode and a metal layer that can serve as an anode, and a drift channel formed of semiconductor material that extends between the ohmic and metal layers. The drift channel includes a heavily doped region adjacent to the ohmic contact layer. The drift channel forms a Schottky barrier with the metal layer. A pinch-off mechanism is provided for pinching off the drift channel while the Schottky diode is reverse-biased. As a result, the level of saturation or leakage current between the metal layer and the ohmic contact layer under a reverse bias condition of the Schottky diode is reduced.

Abstract: A seal ring structure is formed through a multilayer structure of a plurality of dielectric films in a peripheral part of a chip region to surround the chip region. A dual damascene interconnect in which an interconnect and a plug connected to the interconnect are integrated is formed in at least one of the dielectric films in the chip region. Part of the seal ring structure formed in the dielectric film in which the dual damascene interconnect is formed is continuous. A protection film formed on the multilayer structure has an opening on the seal ring. A cap layer connected to the seal ring is formed in the opening.

Abstract: A semiconductor chip includes a circuit region and a corner stress relief (CSR) region. The CSR region is in a corner of the semiconductor chip. A device under test (DUT) structure or a functional circuit is disposed on the circuit region. A probe pad is disposed on the CSR region. A metal line extends from the circuit region to the CSR region to electrically connect the probe pad to the DUT structure or a functional circuit.

Abstract: A seal ring structure for an integrated circuit includes a seal ring being disposed along a periphery of the integrated circuit and being divided into at least a first portion and a second portion, wherein the second portion is positioned facing an analog and/or RF circuit block and is different from the first portion in structure. A P+ region is provided in a P substrate and positioned under the second portion. A shallow trench isolation (STI) structure surrounds the P+ region and laterally extends underneath a conductive rampart of the second portion.

Abstract: A seal ring structure disposed along a periphery of an integrated circuit. The seal ring is divided into at least a first portion and a second portion. The second portion is positioned facing and shielding an analog and/or RF circuit block from a noise. A deep N well is disposed in a P substrate and is positioned under the second portion. The deep N well reduces the substrate noise coupling.

Abstract: A dual triggered silicon controlled rectifier (DTSCR) comprises: a semiconductor substrate; a well region, a first N+ diffusion region, a first P+ diffusion region, a second N+ diffusion region, a second P+ diffusion region, a third P+ diffusion region, positioned in one side of the DTSCR and across the well region and semiconductor substrate; a third N+ diffusion region, positioned in another side of the DTSCR and across the well region and the semiconductor substrate; a first gate, positioned above the semiconductor substrate between the first P+ diffusion region and the third P+ diffusion region, utilized as a P-type trigger node to receive a first trigger current or a first trigger voltage; and a second gate, positioned above the well region between the second N+ diffusion region and the third N+ diffusion region, utilized as an N-type trigger node to receive a second trigger current or a second trigger voltage.

Abstract: A semiconductor power device comprises a semiconductor substrate. The substrate includes an N-type silicon region and N+ silicon region. An oxide layer overlies the N? type silicon region, the oxide layer formed using a Plasma Enhanced Chemical Vapor deposition (PECVD) method. First and second electrodes are coupled to the N? type silicon region and the N+ type silicon region, respectively. The oxide layer has a thickness 0.5 to 3 microns. The power device also includes a polymide layer having a thickness of 3 to 20 microns; a first field plate overlying the oxide layer; and second field plate overlying the polymide layer and the first field plate, wherein the second field plate overlaps the first field plate by 2 to 15 microns.

Abstract: In the specification and drawing a super junction semiconductor device is disclosed. The super junction semiconductor device comprises a P-type layer, a N+ substrate, a N-type layer, a silicon dioxide layer and a P+ layer. The N+ substrate is disposed under the P-type layer. The N-type layer is disposed on the N+ substrate. The silicon dioxide layer is disposed between the N-type layer and the P-type layer. The P+ layer is disposed on the P-type layer and the N-type layer.

Abstract: A semiconductor structure. The semiconductor structure includes a semiconductor substrate, a first transistor on the semiconductor substrate, and a guard ring on the semiconductor substrate. The semiconductor substrate includes a top substrate surface which defines a reference direction perpendicular to the top substrate surface. The guard ring includes a semiconductor material doped with a doping polarity. A first doping profile of a first doped transistor region of the first transistor in the reference direction and a second doping profile of a first doped guard-ring region of the guard ring in the reference direction are essentially a same doping profile. The guard ring forms a closed loop around the first transistor.

Abstract: A dual triggered silicon controlled rectifier (DTSCR) comprises: a semiconductor substrate; an N-well, a P-well, a first N+ diffusion region and a first P+ diffusion region, a second N+ diffusion region and a second P+ diffusion region, a third P+ diffusion region, positioned in one side of the DTSCR and across the N-well and the P-well; a third N+ diffusion region, positioned in another side of the DTSCR and across the N-well and the P-well; a first gate, positioned above the N-well between the second P+ diffusion region and the third P+ diffusion region, for use as a P-type trigger node to receive a first trigger current or a first trigger voltage; and a second gate, positioned above the P-well between the first N+ diffusion region and the third N+ diffusion region, for use as an N-type trigger node to receive a second trigger current or a second trigger voltage.

Abstract: Disclosed are semiconductor devices and methods of making semiconductor devices. An exemplary embodiment comprises a semiconductor layer of a first conductivity type having a first surface, a second surface, and a graded net doping concentration of the first conductivity type within a portion of the semiconductor layer. The graded portion is located adjacent to the top surface of the semiconductor layer, and the graded net doping concentration therein decreasing in value with distance from the top surface of the semiconductor layer. The exemplary device also comprises an electrode disposed at the first surface of the semiconductor layer and adjacent to the graded portion.

Abstract: An embodiment of a process for manufacturing a semiconductor power device envisages the steps of: providing a body made of semiconductor material having a first top surface; forming an active region with a first type of conductivity in the proximity of the first top surface and inside an active portion of the body; and forming an edge-termination structure. The edge-termination structure is formed by: a ring region having the first type of conductivity and a first doping level, set within a peripheral edge portion of the body and electrically coupled to the active region; and a guard region, having the first type of conductivity and a second doping level, higher than the first doping level, set in the proximity of the first top surface and connecting the active region to the ring region.

Abstract: In one embodiment, a semiconductor device is formed in a body of semiconductor material. The semiconductor device includes a charge compensating trench formed in proximity to active portions of the device. The charge compensating trench includes a trench filled with various layers of semiconductor material including opposite conductivity type layers.

Abstract: In one embodiment, a semiconductor device is formed in a body of semiconductor material. The semiconductor device includes a charge compensating trench formed in proximity to active portions of the device. The charge compensating trench includes a trench filled with various layers of semiconductor material including opposite conductivity type layers.