Abstract: A method for forming a semiconductor device includes forming a first guard ring around at least one transistor over a substrate. The method further includes forming a second guard ring around the first guard ring, wherein the second guard ring directly contacts the first guard ring. The method further includes forming an isolation structure between the first guard ring and the second guard ring. The method further includes forming a first doped region adjacent to the first guard ring, the first doped region having a first dopant type. The method further includes forming a second doped region adjacent to the second guard ring, the second doped region having a second dopant type.

Abstract: A diode structure and a manufacturing method are disclosed. The diode structure includes a semiconductor substrate, a first semiconductor layer, a second semiconductor layer and an epitaxy layer. The semiconductor substrate includes a first surface. The first semiconductor layer and the second semiconductor layer are extended toward the interior of the semiconductor substrate from the first surface by implanting a dopant. Both of the semiconductor types of the first semiconductor layer and the second semiconductor layer are opposite to the semiconductor type of the semiconductor substrate. The epitaxy layer is formed on the first surface, connected with the first semiconductor layer and the second semiconductor layer and extended outwardly from the first surface. The first semiconductor layer and the second semiconductor layer are connected with each other, continuously.

Abstract: An object of the present invention is to provide a highly reliable semiconductor device by preventing precipitation of an oxide to prevent peeling of a resin layer. The semiconductor device includes: a resin layer provided so that at least a part of the resin layer extends on a front surface of a semiconductor layer on an outer peripheral side with respect to an outer peripheral end of a field insulating film; and a floating well region spaced apart from a termination well region in a surface layer of the semiconductor layer, the floating well region formed to be in contact with an outer peripheral end of the field insulating film to extend to the outer peripheral side with respect to the outer peripheral end of the field insulating film.

Abstract: A semiconductor device is provided. The semiconductor device includes a first substrate that has a first side for forming memory cells and a second side that is opposite to the first side. The semiconductor device also includes a doped region and a first connection structure. The doped region is formed in the first side of the first substrate and is electrically coupled to at least a source terminal of a transistor (e.g., a source terminal of an end transistor of multiple transistors that are connected in series). The first connection structure is formed over the second side of the first substrate and coupled to the doped region through a first VIA. The first VIA extends from the second side of the first substrate to the doped region.

Abstract: A normally-off first gate channel region is provided on a first main surface side, in a region in a p base between an n base and an n emitter connected to an emitter electrode. On and off of the first gate channel region is controlled by a voltage of a first gate electrode. A normally-on second gate channel region is provided on a second main surface side, by an n-type region between an n collector electrically connected to a collector electrode and the n base. On and off of the second gate channel region is controlled by a voltage of a second gate electrode.

Abstract: A method for forming an integrated circuit includes forming a first guard ring around at least one transistor over a substrate. The method further includes forming a second guard ring around the first guard ring. The method further includes forming a first doped region adjacent to the first guard ring, the first doped region having a first dopant type. The method further includes forming a second doped region adjacent to the second guard ring, the second doped region having a second dopant type.

Abstract: Distributed switches to suppress transient electrical overstress-induced latch-up are provided. In certain configurations, an integrated circuit (IC) or semiconductor chip includes a transient electrical overstress detection circuit that activates a transient overstress detection signal in response to detecting a transient electrical overstress event between a pair of power rails. The IC further includes mixed-signal circuits and latch-up suppression switches distributed across the IC, and the latch-up suppression switches temporarily clamp the power rails to one another in response to activation of the transient overstress detection signal to inhibit latch-up of the mixed-signal circuits.

Abstract: Methods to forming trigger-voltage tunable cascode transistors for an ESD protection circuit in FinFET IC devices and resulting devices. Embodiments include providing a substrate including adjacent first-type well areas, over the substrate, each pair of first-type well areas separated by a second-type well area; providing one or more junction areas in each first and second type well area, each junction area being a first type or a second type; forming fins, spaced from each other, perpendicular to and over the first and second type junction areas; and forming junction-type devices by forming electrical connections between the first and second type junction areas in the first-type well areas and the substrate, wherein a first-stage junction-type device in a first-type well area includes stacked first and second type junction areas, and wherein the first-stage junction-type device is adjacent a second-type well area including first and second type junction areas.

Abstract: Technologies are generally described herein generally relate to tunnel field-effect transistor (TFETs) structures with a gate-on-germanium source (GoGeS) on bulk silicon substrate for sub 0.5V (VDD) operations. In some examples, the GoGeS structure may include an increase in tunneling area and, thereby, a corresponding increases in the ON-state current ION. In order to achieve supersteep sub-threshold swing, both the lateral tunneling due to gate electric-field and the non-uniform tunneling at the gate-edge due to field-induced barrier lowering (FIBL) may be suppressed through selection of component dimension in the device structure. Example devices may be fabricated using CMOS fabrication technologies with the addition of selective etching in the process flow.

Abstract: An improved superjunction semiconductor device includes a charged balanced pylon in a body region, where a top of the pylon is large to create slight charge imbalance. A MOSgated structure is formed over the top of the pylon and designed to conduct current through the pylon. By increasing a dimension of the top of the pylon, the resulting device is less susceptible to variations in manufacturing tolerances to obtain a good breakdown voltage and improved device ruggedness.

Abstract: A semiconductor device includes a p-type semiconductor layer, n-type column regions formed of columnar thermal donors exhibiting an n-type property, a p-type column region interposed between the n-type column regions, the n-type column regions configured to form a super-junction structure in cooperation with the p-type column region, a channel region formed in the semiconductor layer, a source region formed in the channel region, a gate insulator film formed on the semiconductor layer, and a gate electrode formed on the gate insulator film and opposite to the channel region across the gate insulator film.

Abstract: Apparatus and methods for precision mixed-signal electronic circuit protection are provided. In one embodiment, an apparatus includes a p-well, an n-well, a poly-active diode structure, a p-type active region, and an n-type active region. The poly-active diode structure is formed over the n-well, the p-type active region is formed in the n-well on a first side of the poly-active diode structure, and the n-type active region is formed along a boundary of the p-well and the n-well on a second side of the poly-active diode structure. During a transient electrical event the apparatus is configured to provide conduction paths through and underneath the poly-active diode structure to facilitate injection of carriers in the n-type active region. The protection device can further include another poly-active diode structure formed over the p-well to further enhance carrier injection into the n-type active region.

Abstract: A MOSFET device is provided. An N-type epitaxial layer is disposed on an N-type substrate. An insulating trench is disposed in the epitaxial layer. A P-type well region is disposed in the epitaxial layer at one side of the insulating trench. An N-type heavily doped region is disposed in the well region. A gate structure is disposed on the epitaxial layer and partially overlaps with the heavily doped region. At least two P-type first doped regions are disposed in the epitaxial layer below the well region. At least one P-type second doped region is disposed in the epitaxial layer and located between the first doped regions. Besides, the first and second doped regions are separated from each other. The first doped regions extend along a first direction, and the second doped region extends along a second direction different from the first direction.

Abstract: An MOSFET includes a silicon carbide substrate, an active layer, a gate oxide film, and a gate electrode. The active layer includes a body region where an inversion layer is formed at a region in contact with the gate oxide film by application of voltage to the gate electrode. The body region includes a low concentration region arranged at a region where an inversion layer is formed, and containing impurities of low concentration, and a high concentration region adjacent to the low concentration region in the carrier mobile direction in the inversion layer, arranged in a region where the inversion layer is formed, and containing impurities higher in concentration than in the low concentration region.

Abstract: A method of forming a device is disclosed. A substrate defined with a device region is provided. A gate having an upper and a lower portion is formed in a trench in the substrate in the device region. The upper portion forms a gate electrode and the lower portion forms a gate field plate. First and second surface doped regions are formed adjacent to the gate. The gate field plate introduces vertical reduced surface (RESURF) effect in a drift region of the device.

Abstract: A super-junction trench MOSFET with a short termination area is disclosed, wherein the short termination area comprising a charge balance region and a channel stop region formed near a top surface of an epitaxial layer with a trenched termination contact penetrating therethrough.

Abstract: Methods and apparatus for ESD structures. A semiconductor device includes a first active area containing an ESD cell coupled to a first terminal and disposed in a well; a second active area in the semiconductor substrate, the second active area comprising a first diffusion of the first conductivity type for making a bulk contact to the well; and a third active area in the semiconductor substrate, separated from the first and second active areas by another isolation region, a portion of the third active area comprising an implant diffusion of the first conductivity type within a first diffusion of the second conductivity type and adjacent a boundary with the well of the first conductivity type; wherein the third active area comprises a diode coupled to the terminal and reverse biased with respect to the well of the first conductivity type.

Abstract: Disclosed are guard ring structures with an electrically insulated gap in a substrate to reduce or eliminate device coupling of integrated circuit chips, methods of manufacture and design structures. The method includes forming a guard ring structure comprising a plurality of metal layers within dielectric layers. The method further includes forming diffusion regions to electrically insulate a gap in a substrate formed by segmented portions of the guard ring structure.

Abstract: Embodiments of the invention provide increased ESD protection suitable for high-voltage devices. In one embodiment, an internal DMOS circuit is placed in parallel with a lateral NPN ESD clamp. The clamp has both a high holding voltage, above the operating voltage of the DMOS circuit, and a high maximum current before breakdown. The discharge path of the clamp includes a high-voltage lightly doped well containing a low-voltage higher doped well. The dopant of both wells is the same type, and the interface between the two defines a graded junction. The emitter of the entire circuit is grounded and the collector is coupled to the voltage of the DMOS circuit.

Abstract: An integrated circuit having a semiconductor component arrangement and production method is provided. The integrated circuit includes a semiconductor material region having a surface region and being laterally subdivided into a central region and into an edge region. The integrated circuit includes a passivation layer region, an oxide layer, and a VLD zone. The passivation layer region is formed on the surface region in the edge region and is configured to realize a field distribution at the edge of the semiconductor component arrangement. The oxide layer region is provided as a protection against oxidation on and in direct contact with the surface region of the semiconductor material region in the edge region. The oxide layer region or a part of the oxide layer region is formed in direct contact with a channel stopper region formed in the edge 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: Design constraints for a self protecting GaN HFET and in general any group III V HFET are described. The design constraints depend on the separation between the gate and the drain and the thickness of the buffer material between the channel layer and the substrate. In one embodiment the buffer region is thinned to provide a preferred breakdown location.

Abstract: A semiconductor die has multiple discontinuous conductive segments arranged around a periphery of the semiconductor die, and an electrically insulating barrier within discontinuities between the conductive segments. The conductive segments and the barriers form a mechanically continuous seal ring around the semiconductor die.

Abstract: Protection device structures and related fabrication methods are provided. An exemplary semiconductor protection device includes a base well region having a first conductivity type, an emitter region within the base well region having a second conductivity type opposite the first conductivity type, a collector region having the second conductivity type, a first floating region having the second conductivity type within the base well region between the emitter region and the collector region, and a second floating region having the first conductivity type within the base well region between the first floating region and the collector region. The floating regions within the base well region are electrically connected to reduce current gain and improve holding voltage.

Abstract: Protection device structures and related fabrication methods are provided. An exemplary semiconductor protection device includes a first base region of semiconductor material having a first conductivity type, a second base region of semiconductor material having the first conductivity type and a dopant concentration that is less than the first base region, a third base region of semiconductor material having the first conductivity type and a dopant concentration that is greater than the second base region, an emitter region of semiconductor material having a second conductivity type opposite the first conductivity type within the first base region, and a collector region of semiconductor material having the second conductivity type. At least a portion of the second base region resides between the third base region and the first base region and at least a portion of the first base region resides between the emitter region and the collector region.

Abstract: In a first embodiment, an ultra-fast breakover diode has a turn on time TON that is less than 0.3 microseconds, where the forward breakover voltage is greater than +400 volts and varies less than one percent per ten degrees Celsius change. In a second embodiment, a breakover diode has a reverse breakdown voltage that is greater, in absolute magnitude, than the forward breakover voltage, where the forward breakover voltage is greater than +400 volts. In a third embodiment, a string of series-connected breakover diode dice is provided, along with a resistor string, in a packaged circuit. The packaged circuit acts like a single breakover diode having a large forward breakover voltage and a comparably large reverse breakdown voltage, even though the packaged circuit includes no discrete high voltage reverse breakdown diode. The packaged circuit is usable to supply a triggering current to a thyristor in a voltage protection circuit.

Abstract: An integrated circuit containing a voltage divider having an upper resistor of unsilicided gate material over field oxide around a central opening and a drift layer under the upper resistor, an input terminal coupled to an input node of the upper resistor adjacent to the central opening in the field oxide and coupled to the drift layer through the central opening, a sense terminal coupled to a sense node on the upper resistor opposite from the input node, a lower resistor with a sense node coupled to the sense terminal and a reference node, and a reference terminal coupled to the reference node. A process of forming the integrated circuit containing the voltage divider.

Abstract: A semiconductor device is provided that comprises a semiconductor substrate comprising an active area and a peripheral region adjacent the active area and structure positioned in the peripheral region for hindering the diffusion of mobile ions from the peripheral region into the active area.

Abstract: An integrated circuit contains a voltage protection structure having a diode isolated DENMOS transistor with a guard element proximate to the diode and the DENMOS transistor. The guard element includes an active area coupled to ground. The diode anode is connected to an I/O pad. The diode cathode is connected to the DENMOS drain. The DENMOS source is grounded. A process of forming the integrated circuit is also disclosed.

Abstract: A semiconductor device includes an active section for a main current flow and a breakdown withstanding section for breakdown voltage. An external peripheral portion surrounds the active section on one major surface of an n-type semiconductor substrate. The breakdown withstanding section has a ring-shaped semiconductor protrusion, with a rectangular planar pattern including a curved section in each of four corners thereof, as a guard ring. The ring-shaped semiconductor protrusion has a p-type region therein, is sandwiched between a plurality of concavities deeper than the p-type region, and has an electrically conductive film across an insulator film on the surface thereof. Because of this, it is possible to manufacture at low cost a breakdown withstanding structure with which a high breakdown voltage is obtained in a narrow width, wherein there is little drop in breakdown voltage, even when there are variations in a patterning process of a field oxide film.

Abstract: A semiconductor rectifier device includes a semiconductor substrate of a first conductive type of a wide gap semiconductor; a semiconductor layer of the first conductive type of the wide gap semiconductor formed on an upper surface of the semiconductor substrate, wherein an impurity concentration of the semiconductor layer is between 1E+14 atoms/cm3 and 5E+16 atoms/cm3 inclusive, and a thickness thereof is 8 ?m or more; a first semiconductor region of the first conductive type of the wide gap semiconductor formed at the semiconductor layer surface; a plurality of second semiconductor regions of a second conductive type of the wide gap semiconductor formed as sandwiched by the first semiconductor regions, wherein a width of each of the second semiconductor regions is 15 ?m or more; a first electrode formed on the first and second semiconductor regions; and a second electrode formed on a lower surface of the semiconductor substrate.

Abstract: Device structures and design structures that include a silicon controlled rectifier, as well as fabrication methods for such device structures. A well is formed in the device layer of a silicon-on-insulator substrate. A silicon controlled rectifier is formed that includes an anode in the well. A deep trench capacitor is formed that includes a plate coupled with the well. The plate of the deep trench capacitor extends from the device layer through a buried insulator layer of the silicon-on-insulator substrate and into a handle wafer of the silicon-on-insulator substrate.

Abstract: An embodiment of a semiconductor power device provided with: a structural body made of semiconductor material with a first conductivity, having an active area housing one or more elementary electronic components and an edge area delimiting externally the active area; and charge-balance structures, constituted by regions doped with a second conductivity opposite to the first conductivity, extending through the structural body both in the active area and in the edge area in order to create a substantial charge balance. The charge-balance structures are columnar walls extending in strips parallel to one another, without any mutual intersections, in the active area and in the edge area.

Abstract: This invention discloses a semiconductor power device disposed in a semiconductor substrate comprising a lightly doped layer formed on a heavily doped layer and having an active cell area and an edge termination area. The edge termination area comprises a plurality P-channel MOSFETs. By connecting the gate to the drain electrode, the P-channel MOSFET transistors formed on the edge termination are sequentially turned on when the applied voltage is equal to or greater than the threshold voltage Vt of the P-channel MOSFET transistors, thereby optimizing the voltage blocked by each region.

Abstract: Junction-isolated blocking voltage devices and methods of forming the same are provided. In certain implementations, a blocking voltage device includes an anode terminal electrically connected to a first p-well, a cathode terminal electrically connected to a first n-well, a ground terminal electrically connected to a second p-well, and an n-type isolation layer for isolating the first p-well from a p-type substrate. The first p-well and the first n-well operate as a blocking diode. The blocking voltage device further includes a PNPN silicon controlled rectifier (SCR) associated with a P+ region formed in the first n-well, the first n-well, the first p-well, and an N+ region formed in the first p-well. Additionally, the blocking voltage device further includes an NPNPN bidirectional SCR associated with an N+ region formed in the first p-well, the first p-well, the n-type isolation layer, the second p-well, and an N+ region formed in the second p-well.

Abstract: A method of forming a device is disclosed. The method includes providing a substrate having a device region. The device region includes a source region, a gate region and a drain region defined thereon. The substrate is prepared with gate layers on the substrate. The gate layers are patterned to form a gate in the gate region and a field structure surrounding the drain region. A source and a drain are formed in the source region and drain region respectively. The drain is separated from the gate on a second side of the gate and the source is adjacent to a first side of the gate. An interconnection to the field structure is formed. The interconnection is coupled to a potential which distributes the electric field across the substrate between the second side of the gate and the drain.

Abstract: A second conduction-type MIS transistor in which a source is coupled to a second power source over the surface of a first conduction-type well and a drain is coupled to the open-drain signal terminal is provided. A second conduction-type first region is provided at both sides of the MIS transistor in parallel with a direction where the electric current of the MIS transistor flows and coupled to the open-drain signal terminal. The whole these components are surrounded by a first conduction-type guard ring coupled to the second power source and the outside surrounded by the first conduction-type guard ring is further surrounded by a second conduction-type guard ring coupled to a first power source. Thereby, the semiconductor device is capable of achieving ESD protection of an open-drain signal terminal having a small area and not providing a protection element between power source terminals.

Abstract: A method for forming an integrated circuit. The method includes forming a first guard ring around at least one transistor over a substrate, the first guard ring having a first type dopant. The method further includes forming a second guard ring around the first guard ring, the second guard ring having a second type dopant. The method includes forming a first doped region adjacent to the first guard ring, the first doped region having the second type dopant. The method further includes forming a second doped region adjacent to the second guard ring, the second doped region having the first type dopant, wherein the first guard ring, the second guard ring, the first doped region, and the second doped region are capable of being operable as a first silicon controlled rectifier (SCR) to substantially release an electrostatic discharge (ESD).

Abstract: Apparatus and methods for electronic circuit protection under high stress operating conditions are provided. In one embodiment, an apparatus includes a substrate having a first p-well, a second p-well adjacent the first p-well, and an n-type region separating the first and second p-wells. An n-type active area is over the first p-well and a p-type active area is over the second p-well. The n-type and p-type active areas are electrically connected to a cathode and anode of a high reverse blocking voltage (HRBV) device, respectively. The n-type active area, the first p-well and the n-type region operate as an NPN bipolar transistor and the second p-well, the n-type region, and the first p-well operate as a PNP bipolar transistor. The NPN bipolar transistor defines a relatively low forward trigger voltage of the HRBV device and the PNP bipolar transistor defines a relatively high reverse breakdown voltage of the HRBV device.

Abstract: An integrated trench-MOS-controlled-thyristor plus trench gated diode combination, in which the trenches are preferably formed at the same time. A backside polarity reversal process permits a backside p+ region in the thyristor areas, and only a backside n+ region in the diode areas (for an n-type device). This is particularly advantageous in motor control circuits and the like, where the antiparallel diode permits the thyristor to be dropped into existing power MOSFET circuit designs. In power conversion circuits, the antiparallel diode can conveniently serve as a freewheeling diode.

Abstract: On a single-crystal substrate, a drift layer is formed. The drift layer has a first surface facing the single-crystal substrate, and a second surface opposite to the first surface, is made of silicon carbide, and has first conductivity type. On the second surface of the drift layer, a collector layer made of silicon carbide and having second conductivity type is formed. By removing the single-crystal substrate, the first surface of the drift layer is exposed. A body region and an emitter region are formed. The body region is disposed in the first surface of the drift layer, and has the second conductivity type different from the first conductivity type. The emitter region is disposed on the body region, is separated from the drift layer by the body region, and has first conductivity type.

Abstract: An embodiment of the disclosed technology provides a method for preventing electrostatic breakdown during the manufacturing process of the array substrate. The method comprises: when forming a conductive pattern of a substrate, connecting conductive lines for forming the conductive pattern with a closed conductive ring on a same layer as the conductive lines in a peripheral region of the substrate, and wherein when electrostatic charges are generated over the metal line, the electrostatic charges are led to the closed conductive ring.

Abstract: The invention relates to a power semiconductor device and its preparation methods thereof. Particularly, the invention aims at providing a method for reducing substrate contribution to the Rdson (drain-source on resistance) of power MOSFETs, and a power MOSFET device made by the method. By forming one or more bottom grooves at the bottom of Si substrate, the on resistance of the power MOSFET device attributed to the substrate is effectively reduced. A matching lead frame base complementary to the substrate with bottom grooves further improves the package of the power MOSFET device.

Abstract: The invention provides an LDMOS transistor of which the time-dependent degrading of the performance due to the trapping of hot electrons in the gate insulation film is decreased. A body layer is disposed in a surface portion of an N?? type semiconductor layer. A source layer including an N? type layer is disposed in a surface portion of the body layer. An N? type drift layer is formed in a surface portion of the N?? type semiconductor layer. This drift layer includes a first region having a first N type impurity concentration peak region and a second region having a second N type impurity concentration peak region that is positioned deeper than the first N type impurity concentration peak region, the second region adjoining this first region. An N+ type drain layer is formed in a surface portion of the second region.

Abstract: A thyristor device includes a semiconductor body and a conductive anode. The semiconductor body has a plurality of doped layers forming a plurality of dopant junctions and includes an optical thyristor, a first amplifying thyristor, and a switching thyristor. The conductive anode is disposed on a first side of the semiconductor body. The optical thyristor is configured to receive incident radiation to generate a first electric current, and the first amplifying thyristor is configured to increase the first electric current from the optical thyristor to at least a threshold current. The switching thyristor switches to the conducting state in order to conduct a second electric current from the anode and through the semiconductor body.

Abstract: A trench MOS structure is provided. The trench MOS structure includes a substrate, an epitaxial layer, a trench, a gate isolation, a trench gate, a guard ring and a reinforcement structure within the guard ring. The substrate has a first conductivity type, a first side and a second side opposite to the first side. The epitaxial layer has the first conductivity type and is disposed on the first side. The trench is disposed in the epitaxial layer. The gate isolation covers the inner wall of the trench. The trench gate is disposed in the trench and has the first conductivity type. The guard ring has a second conductivity type and is disposed within the epitaxial layer. The reinforcement structure has an electrically insulating material and is disposed within the guard ring.

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: A trench semiconductor power device with a termination area structure is disclosed. The termination area structure comprises a wide trench and a trenched field plate formed not only along trench sidewall but also on trench bottom of the wide trench by doing poly-silicon CMP so that the body ion implantation is blocked by the trenched field plate on the trench bottom to prevent the termination area underneath the wide trench from being implanted. Moreover, a contact mask is used to define both trenched contacts and source regions of the device for saving a source mask.

Abstract: A semiconductor element, a manufacturing method thereof and an operating method thereof are provided. The semiconductor element includes a substrate, a first well, a second well, a third well, a fourth well, a bottom layer, a first heavily doping region, a second heavily doping region, a third heavily doping region and a field plane. The first well, the bottom layer and the second well surround the third well for floating the third well and the substrate. The first, the second and the third heavily doping regions are disposed in the first, the second and the third wells respectively. The field plate is disposed above a junction between the first well and the fourth well.

Abstract: A transistor comprising a plurality of active semiconductor layers on a substrate, with source and drain electrodes in contact with the semiconductor layers. A gate is formed between the source and drain electrodes and on the plurality of semiconductor layers. A plurality of field plates are arranged over the semiconductor layers, each of which extends from the edge of the gate toward the drain electrode, and each of which is isolated from said semiconductor layers and from the others of the field plates. The topmost of the field plates is electrically connected to the source electrode and the others of the field plates are electrically connected to the gate or the source electrode.