Abstract: A pressure sensor (1) is provided which has a piezoresistive membrane (2) which can be deformed by the action of the pressure of a medium. The membrane (2) is arranged on a carrier substrate (3) and extends over an opening (32) in the carrier substrate (3). The pressure sensor (1) has a protective layer (4) to protect the membrane (2) from direct contact with a medium. The protective layer (4) covers the membrane (2) both in a first region (28) inside the opening (32) and in a second region (29) outside the opening (32). Furthermore, a process for producing a pressure sensor (1) is provided in which the protective layer (4) forms an etch stop for an etching process.

Abstract: An encapsulated MEMS device and a method to form an encapsulated MEMS device are described. An apparatus includes a first substrate having a silicon-germanium seal ring disposed thereon and a second substrate having a metal seal ring disposed thereon. The metal seal ring is aligned with and bonded to the silicon-germanium seal ring to provide a sealed cavity. A MEMS device is housed in the sealed cavity. A method includes forming a silicon-germanium seal ring on a first substrate and forming a metal seal ring on a second substrate. The metal seal ring is bonded to the silicon-germanium seal ring to provide a sealed cavity that houses a MEMS device.

Abstract: An integrated MEMS device comprises a wafer where the wafer contains two or more cavities of different depths. The MEMS device includes one movable structure within a first cavity of a first depth and a second movable structure within a second cavity of a second depth. The cavities are sealed to maintain different pressures for the different movable structures for optimal operation. MEMS stops can be formed in the same multiple cavity depth processing flow. The MEMS device can be integrated with a CMOS wafer.

Abstract: A sensing unit package with reduced size and improved thermal sensing capabilities. An exemplary package includes a printed circuit board with a plurality of electrical traces, an application-specific integrated circuit (Analog ASIC) chip, and a micromachined sensor formed on a microelectromechanical system (MEMS) die. The Analog ASIC chip is electrically and mechanically attached to the printed circuit board. The MEMS die is in direct electrical communication with only a portion of the electrical traces of the printed circuit board and is mechanically and thermally attached directly to the Analog ASIC chip. A thermally conducting compound is located between the MEMS die and the Analog ASIC chip. One or more solder balls electrically attach the Analog ASIC chip to the printed circuit board and one or more solder traces electrically attach the MEMS die to the printed circuit board.

Abstract: A micromechanical component including a first composite of a plurality of semiconductor chips, the first composite having a first front and back surfaces, a second composite of a corresponding plurality of carrier substrates, the second composite having a second front and back surfaces; wherein the first front surface and the second front surface are connected via a structured adhesion promoter layer in such a way that each semiconductor chip is connected, essentially free of cavities, to a corresponding carrier substrate corresponding to a respective micromechanical component.

Abstract: A semiconductor device includes a semiconductor substrate and a semiconductor mass element configured to move in response to an applied acceleration. The mass element is defined by trenches etched into the semiconductor substrate and a cavity below the mass element. The semiconductor device includes a sensing element configured to sense movement of the mass element.

Abstract: A system and method for providing a MEMS device with integrated electronics are disclosed. The MEMS device comprises an integrated circuit substrate and a MEMS subassembly coupled to the integrated circuit substrate. The integrated circuit substrate includes at least one circuit coupled to at least one fixed electrode. The MEMS subassembly includes at least one standoff formed by a lithographic process, a flexible plate with a top surface and a bottom surface, and a MEMS electrode coupled to the flexible plate and electrically coupled to the at least one standoff. A force acting on the flexible plate causes a change in a gap between the MEMS electrode and the at least one fixed electrode.

Abstract: A method and system for providing a MEMS device with a portion exposed to an outside environment are disclosed. The method comprises bonding a handle wafer to a device wafer to form a MEMS substrate with a dielectric layer disposed between the handle and device wafers. The method includes lithographically defining at least one standoff on the device wafer and bonding the at least one standoff to an integrated circuit substrate to form a sealed cavity between the MEMS substrate and the integrated circuit substrate. The method includes defining at least one opening in the handle wafer, standoff, or integrated circuit substrate to expose a portion of the to expose a portion of the device wafer to the outside environment.

Abstract: A thin film transistor and a press sensing device using the thin film transistor are disclosed. The thin film transistor, comprises a source electrode; a drain electrode spaced from the source electrode; a semiconductor layer electrically connected with the source electrode and the drain electrode, a channel defined in the semiconductor layer and located between the source electrode and the drain electrode; and a gate electrode electrically insulated from the semiconductor layer; and an insulative layer configured for insulating the source electrode, the drain electrode, and the semiconductor layer from each other, wherein the insulative layer is made of a polymeric material with an elastic modulus ranged from about 0.1 megapascal (MPa) to about 10 MPa.

Abstract: A diaphragm of an MEMS electroacoustic transducer including a first axis-symmetrical pattern layer is provided. Because the layout of the first axis-symmetrical pattern layer can match the pattern of the sound wave, the vibration uniformity of the diaphragm can be improved.

Abstract: A process for manufacturing a MEMS device, wherein a bottom silicon region is formed on a substrate and on an insulating layer; a sacrificial region of dielectric is formed on the bottom region; a membrane region, of semiconductor material, is epitaxially grown on the sacrificial region; the membrane region is dug down to the sacrificial region so as to form through apertures; the side wall and the bottom of the apertures are completely coated in a conformal way with a porous material layer; at least one portion of the sacrificial region is selectively removed through the porous material layer and forms a cavity; and the apertures are filled with filling material so as to form a monolithic membrane suspended above the cavity. Other embodiments are directed to MEMS devices and pressure sensors.

Abstract: The present disclosure provides a system of fabricating a microstructure device with an improved anchor. A method of fabricating a microstructure device with an improved anchor includes providing a substrate and forming an oxide layer on the substrate. Then, a cavity is etched in the oxide layer, such that the cavity includes a sidewall in the oxide layer. A microstructure device layer is then bonded to the oxide layer over the cavity. Forming a microstructure device, a trench is etched in the device layer to define an outer boundary of the microstructure device. In an embodiment, the outer boundary is substantially outside of the sidewall of the cavity. Then, the sidewall of the cavity is etched away through the trench in the device layer, to thereby suspend the microstructure device over the cavity.

Abstract: An improved method for manufacturing an MEMS microphone with a double fixed electrode is specified which results in a microphone which likewise has improved properties.

Abstract: A Microelectromechanical systems (MEMS) structure comprises a MEMS wafer. A MEMS wafer includes a handle wafer with cavities bonded to a device wafer through a dielectric layer disposed between the handle and device wafers. The MEMS wafer also includes a moveable portion of the device wafer suspended over a cavity in the handle wafer. Four methods are described to create two or more enclosures having multiple gas pressure or compositions on a single substrate including, each enclosure containing a moveable portion. The methods include: A. Forming a secondary sealed enclosure, B. Creating multiple ambient enclosures during wafer bonding, C. Creating and breaching an internal gas reservoir, and D. Forming and subsequently sealing a controlled leak/breach into the enclosure.

Abstract: The present invention relates to a conductive nanomembrane and a Micro Electro Mechanical System sensor using the same, and more particularly, a conductive nanomembrane that is formed by stacking a polymer electrolyte film and a carbon nanotube layer, and a MEMS sensor using the same.

Abstract: A MEMS sensor formed by processing a multi-layer wiring structure, includes: a movable weight portion coupled to a fixed frame portion with an elastic deformable portion and having a hollow portion formed at the periphery; a capacitance electrode portion including a fixed electrode portion fixed to the fixed frame portion and a movable electrode portion connected to the movable weight portion and arranged to face the fixed electrode portion; and an adjusting layer for adjusting at least one of amass of the movable weight portion, a damping coefficient of the movable electrode portion, and spring characteristics in the elastic deformable portion, wherein the adjusting layer includes at least one insulating layer that is a constituent element of the multi-layer wiring structure.

Abstract: A MEMS may integrate movable MEMS parts, such as mechanical elements, flexible membranes, and sensors, with the low-cost device package, leaving the electronics and signal-processing parts in the integrated circuitry of the semiconductor chip. The package may be a leadframe-based plastic molded body having an opening through the thickness of the body. The movable part may be anchored in the body and extend at least partially across the opening. The chip may be flip-assembled to the leads to span across the foil, and may be separated from the foil by a gap. The leadframe may be a prefabricated piece part, or may be fabricated in a process flow with metal deposition on a sacrificial carrier and patterning of the metal layer. The resulting leadframe may be flat or may have an offset structure useful for stacked package-on-package devices.

Abstract: An MEMS microphone is bonded onto the surface of an IC component containing at least one integrated circuit suitable for the conditioning and processing of the electrical signal supplied by the MEMS microphone. The entire component is simple to produce and has a compact and space-saving construction. Production is accomplished in a simple and reliable manner.

Abstract: The present invention relates to a CMOS compatible MEMS microphone, comprising: an SOI substrate, wherein a CMOS circuitry is accommodated on its silicon device layer; a microphone diaphragm formed with a part of the silicon device layer, wherein the microphone diaphragm is doped to become conductive; a microphone backplate including CMOS passivation layers with a metal layer sandwiched and a plurality of through holes, provided above the silicon device layer, wherein the plurality of through holes are formed in the portions thereof opposite to the microphone diaphragm, and the metal layer forms an electrode plate of the backplate; a plurality of dimples protruding from the lower surface of the microphone backplate opposite to the diaphragm; and an air gap, provided between the diaphragm and the microphone backplate, wherein a spacer forming a boundary of the air gap is provided outside of the diaphragm or on the edge of the diaphragm; wherein a back hole is formed to be open in substrate underneath the diaph

Abstract: Electrical energy generation apparatuses, in which a solar battery device and a piezoelectric device are combined in a single body by using a plurality of nano wires formed of a semiconductor material having piezoelectric properties.

Abstract: In one embodiment, a method of manufacturing a semiconductor device includes oxidizing a substrate to form local oxide regions that extend above a top surface of the substrate. A membrane layer is formed over the local oxide regions and the top surface of the substrate. A portion of the substrate under the membrane layer is removed. The local oxide regions under the membrane layer is removed.

Abstract: A method of manufacturing a microphone using epitaxially grown silicon. A monolithic wafer structure is provided. A wafer surface of the structure includes poly-crystalline silicon in a first horizontal region and mono-crystalline silicon in a second horizontal region surrounding a perimeter of the first horizontal region. A hybrid silicon layer is epitaxially deposited on the wafer surface. Portions of the hybrid silicon layer that contact the poly-crystalline silicon use the poly-crystalline silicon as a seed material and portions that contact the mono-crystalline silicon use the mono-crystalline silicon as a seed material. As such, the hybrid silicon layer includes both mono-crystalline silicon and poly-crystalline silicon in the same layer of the same wafer structure. A CMOS/membrane layer is then deposited on top of the hybrid silicon layer.

Abstract: A method and apparatus are disclosed for reducing stiction in MEMS devices. The method comprises patterning a CMOS wafer to expose Titanium-Nitride (TiN) surface for a MEMS stop and patterning the TiN to form a plurality of stop pads on the top metal aluminum surface of the CMOS wafer. The method is applied for a moveable MEMS structure bonded to a CMOS wafer. The TiN surface and/or plurality of stop pads minimize stiction between the MEMS structure and the CMOS wafer. Further, the TiN film on top of aluminum electrode suppresses the formation of aluminum hillocks which effects the MEMS structure movement.

Abstract: A device includes a die having: at least one of an electronic device and a microelectromechanical system, a package substrate, an electrically nonconductive interposer disposed between the die and the package substrate, at least a first adhesive layer disposed between the package substrate and the electrically nonconductive interposer, and at least a second adhesive layer disposed between the die and the electrically nonconductive interposer.

Abstract: A device comprises a conductive substrate, a micro electromechanical systems (MEMS) structure, and a plurality of bond pads. The conductive substrate has a first side and a second side, the second side opposite the first side. The MEMS structure is formed over the first side of the conductive substrate. The plurality of bond pads are formed over the first side of the conductive substrate and electrically coupled to the first side of the conductive substrate. The conductive substrate and plurality of bond pads function to provide electrostatic shielding to the MEMS structure.

Abstract: A method of packaging a micro electro-mechanical structure comprises forming said structure on a substrate; depositing a sacrificial layer over said structure; patterning the sacrificial layer; depositing a SIPOS (semi-insulating polycrystalline silicon) layer over the patterned sacrificial layer; treating the SIPOS layer with an etchant to convert the SIPOS layer into a porous SIPOS layer, removing the patterned sacrificial layer through the porous layer SIPOS to form a cavity including said structure; and sealing the porous SIPOS layer. A device including such a packaged micro electro-mechanical structure is also disclosed.

Abstract: An MEMS component including a monolithically integrated electronic component with a multi-plane conductor track layer stack which is arranged on a substrate and into which is integrated a cantilevered elastically movable metallic actuator which is arranged in the multi-plane conductor track layer stack at the level of a conductor track plane and is connected by via contacts to conductor track planes which are arranged thereabove or therebeneath and which apart from an opening in the region of the actuator are separated from the conductor track plane of the actuator by a respective intermediate plane insulator layer, wherein the actuator is formed from a metallically conductive layer or layer combination which is resistant to corrosive liquids or gases and which contains titanium nitride or consists of titanium nitride.

Abstract: A semiconductor sensor die is packaged with a footed lid that has side walls and a top portion with a central hole. Gel material is dispensed into a cavity formed by the side walls such that it covers the die prior to attaching the lid top portion.

Abstract: Disclosed is a method for bonding semiconductor substrates, wherein an eutectic alloy does run off the bonding surfaces during the eutectic bonding. Also disclosed is an MEMS device which is obtained by bonding semiconductor substrates by this method. Specifically, a substrate (11) and a substrate (21) are eutectically bonded with each other by pressing and heating the substrate (11) and the substrate (21), while interposing an aluminum-containing layer (31) and a germanium layer (32) between a bonding part (30a) of the substrate (11) and a bonding part (30b) of the substrate (21) in such a manner that the aluminum-containing layer (31) and the germanium layer (32) overlap each other, with an outer edge (32a) of the germanium layer (32) being inwardly set back from the an outer edge (31a) of the aluminum-containing layer (31).

Abstract: A semiconductor device and method for manufacturing. One embodiment provides a semiconductor device including an active cell region and a gate pad region. A conductive gate layer is arranged in the active cell region and a conductive resistor layer is arranged in the gate pad region. The resistor layer includes a resistor region which includes a grid-like pattern of openings formed in the resistor layer. A gate pad metallization is arranged at least partially above the resistor layer and in electrical contact with the resistor layer. An electrical connection is formed between the gate layer and the gate pad metallization, wherein the electrical connection includes the resistor region.

Abstract: A method of bonding a semiconductor substrate in which a first semiconductor substrate is bonded with a second semiconductor substrate by eutectic bonding with pressurization and heating, an aluminum containing layer primarily made of aluminum and a germanium layer in a polymer state being interposed between a bonding surface of the first semiconductor substrate and a bonding surface of the second semiconductor substrate, the method including a step of: setting a weight ratio of the germanium layer to an aluminum containing layer to be eutectic alloyed is between 27 wt % to 52 wt %.

Abstract: A method to prevent movable structures within a MEMS device, and more specifically, in recesses having one or more dimension in the micrometer range or smaller (i.e., smaller than about 10 microns) from being inadvertently bonded to non-moving structures during a bonding process. The method includes surface preparation of silicon both structurally and chemically to aid in preventing moving structures from bonding to adjacent surfaces during bonding, including during high force, high temperature fusion bonding.

Abstract: An arrangement and a production method for the arrangement with at least one MEMS device, which comprises a package that closely encloses the MEMS device and seals it from ambient influences. The package comprises as sealing a PFPE layer of a perfluoropolyether polymerized with the aid of functional groups.

Abstract: A MEMS accelerometer uses capacitive sensing between two electrode layers. One of the electrode layers has at least four independent electrodes arranged as two pairs of electrodes, with one pair aligned orthogonally to the other such that tilting of the membrane can be detected as well as normal-direction movement of the membrane. In this way, a three axis accelerometer can be formed from a single suspended mass, and by sensing using a set of capacitor electrodes which are all in the same plane. This means the fabrication is simple and is compatible with other MEMS manufacturing processes, such as MEMS microphones.

Abstract: A micro-electromechanical system (MEMS) device includes a substrate, a first beam, a second beam, and a third beam. The first beam includes first and second portions separated by an isolation joint. The first and second portions each comprise a semiconductor and a first dielectric layer. An electrically conductive trace is mechanically coupled to the first beam and electrically coupled to the second portion's semiconductor but not the first portion's semiconductor. The second beam includes a second dielectric layer. The profile of each of the first second, and third beams has been formed by a dry etch. A cavity separates a surface of the substrate from the first, second, and third beams. The cavity has been formed by a dry etch. A side wall of each of the first, second, and third beams has substantially no dielectric layer disposed thereon, and the dielectric layer has been removed by a vapor-phase etch.

Abstract: A package structure having MEMS elements includes: a wafer having MEMS elements, electrical contacts and second alignment keys; a plate disposed over the MEMS elements and packaged airtight; transparent bodies disposed over the second alignment keys via an adhesive; an encapsulant disposed on the wafer to encapsulate the plate, the electrical contacts and the transparent bodies; bonding wires embedded in the encapsulant and each having one end connecting a corresponding one of the electrical contacts and the other end exposed from a top surface of the encapsulant; and metal traces disposed on the encapsulant and electrically connected to the electrical contacts via the bonding wires. The present invention eliminates the need to form through holes in a silicon substrate as in the prior art so as to reduce fabrication costs. Further, the present invention accomplishes wiring processes by using a common alignment device to thereby reduce equipment costs.

Abstract: A piezoresistive pressure sensor is provided, which can prevent the occurrence of ESD breakdown due to the nearness of interconnection layers of a resistive element according to miniaturization thereof. The piezoresistive pressure sensor is so configured that respective semiconductor resistive layers on both sides of an arrangement are formed to be relatively longer than an adjacent semiconductor resistive layer, and thus a corner portion of a semiconductor connection layer that extends from the respective semiconductor resistive layers on both sides of the arrangement and a corner portion of the semiconductor interconnection layer that is nearest to the corner portion of the semiconductor connection layer, between which the ESD breakdown occurs easily, can be separated from each other.

Abstract: An electronic MEMS device is formed by a chip having with a main face and bonded to a support via an adhesive layer. A cavity extends inside the chip from its main face and is closed by a flexible film covering the main face of the chip at least in the area of the cavity. The support has a depressed portion facing the cavity and delimited by a protruding portion facing the main face of the chip. Inside the depressed portion, the adhesive layer has a greater thickness than the projecting portion so as to be able to absorb any swelling of the flexible film as a result of the expansion of the gas contained inside the cavity during thermal processes.

Abstract: Processes and fixtures for producing electromechanical devices, and particularly three-dimensional electromechanical devices such as inertial measurement units (IMUs), through the use of a fabrication process and a three-dimensional assembly process that entail joining single-axis device-IC chips while positioned within a mounting fixture that maintains the orientations and relative positions of the chips during the joining operation.

Abstract: Improved nano-electromechanical system devices and structures and systems and techniques for their fabrication. In one embodiment, a structure comprises an underlying substrate separated from first and second anchor points by first and second insulating support points, respectively. The first and second anchor points are joined by a beam. First and second deposition regions overlie the first and second anchor points, respectively, and the first and second deposition regions exert compression on the first and second anchor points, respectively. The compression on the first and second anchor points causes opposing forces on the beam, subjecting the beam to a tensile stress. The first and second deposition regions suitably exhibit an internal tensile stress having an achievable maximum varying with their thickness, so that the tensile stress exerted on the beam depends at least on part on the thickness of the first and second deposition regions.

Abstract: A sensor element includes: a first substrate in which a diaphragm is configured on a main surface; a second substrate which is provided on the side opposite to the diaphragm of the first substrate; a cavity which is provided just below the diaphragm of the first substrate; a bonding position which is provided at a bonding position between the first substrate and the second substrate for airtight sealing of the cavity; and a bump portion which is provided at the fitting portion, and protects a fitted state between the first substrate and the second substrate.

Abstract: MEMS and fabrication techniques for positioning the center of mass of released structures in MEMS are provided. A released structure may include a member with a recess formed into an end face of its free end. A released structure may include a plurality of members, with the longitudinal lengths of the members being of differing lengths. Mass of a member disposed below a plane of a flexure may be balanced by mass of a second substrate affixed to the member. In an embodiment, a mirror substrate is affixed to a member partially released from a first substrate and a through hole formed in the second substrate is accessed to complete release of the member.

Abstract: Processes are provided herein for the fabrication of MEMS utilizing both a primary metal that is integrated into the final MEMS structure and two or more sacrificial secondary metals that provide structural support for the primary metal component during machining. A first secondary metal is thinly plated around the primary metal and over the entire surface of the substrate without using photolithography. A second secondary metal, is then thickly plated over the deposited first secondary metal without using photolithography. Additionally, techniques are disclosed to increase the deposition rate of the first secondary metal between primary metal features in order to prevent voiding and thus enhance structural support of the primary metal during machining.

Abstract: The present invention provides a pressure sensor and a method of manufacturing the same, which can change resistance to load smoothly in a relatively small load range and detect the pressure to the extent of relatively large load range. An uneven layer 6 is formed of a resin containing non-conductive particles 6a and having insulation properties, on a surface of the second substrate 3, and a resistor layer 7 containing at least carbon powder and having a certain film thickness is formed on a surface of the uneven layer 6. A sum of a film thickness of the uneven layer 6 between the non-conductive particles 6a and a film thickness of the resistor layer 7 is smaller than a particle diameter of non-conductive particles 6a included in the uneven layer, and at least a resistor layer 7 is formed on the non-conductive particles 6a and between the non-conductive particles 6a.

Abstract: In an acceleration sensor, a sensor unit includes a weight portion having a recess section with one open surface and a solid section one-piece formed with the recess section, beam portions for rotatably supporting the weight portion such that the recess section and the solid section are arranged along a rotation direction, a movable electrode, fixed electrodes, detection electrodes electrically connected to the fixed electrodes to detect a capacitance between the movable electrode and the fixed electrodes. A fixed plate is arranged in a spaced-apart relationship with a surface of the weight portion on which the movable electrode is provided, and embedment electrodes are embedded in the fixed plate to extend along a thickness direction of the fixed plate, the embedment electrodes having one end portions facing the movable electrode to serve as the fixed electrodes and the other end portions configured to serve as the detection electrodes.

Abstract: A component includes at least one MEMS component and at least one additional semiconductor component in a common housing having at least one access opening. On the front side of the MEMS component, at least one diaphragm structure is provided, which spans a cavity on the backside of the MEMS component. The housing includes a carrier, on which the MEMS component is mounted. The MEMS component is mounted, using its front side, on the carrier, so that there is a standoff between the diaphragm structure and the carrier surface. The at least one additional semiconductor component is connected to the backside of the MEMS component, so that the MEMS component and the semiconductor component form a chip stack.

Abstract: An apparatus, method for manufacturing the apparatus, and method for processing a substrate using the apparatus are disclosed. An exemplary apparatus includes a substrate having a plurality of cells, wherein each cell includes a cell structure. The cell structure includes a piezoelectric film portion and a tip disposed over the piezoelectric film portion. The tip is physically coupled with the piezoelectric film portion.

Abstract: Semiconductor-centered MEMS (100) integrates the movable MEMS parts, such as mechanical elements, flexible membranes, and sensors, with the low-cost device package, and leaving only the electronics and signal-processing parts in the integrated circuitry of the semiconductor chip. The package is substrate-based and has an opening through the thickness of the substrate. Substrate materials include polymer tapes with attached metal foil, and polymer-based and ceramic-based multi-metal-layer dielectric composites with attached metal foil. The movable part is formed from the metal foil attached to a substrate surface and extends at least partially across the opening. The chip is flip-assembled to span at least partially across the membrane, and is separated from the membrane by a gap.

Abstract: A MEMS device assembly (20) includes a MEMS die (22) and an integrated circuit (IC) die (24). The MEMS die (22) includes a MEMS device (36) formed on a substrate (38) and a cap layer (34). A packaging process (72) entails forming the MEMS device (36) on the substrate (38) and removing a material portion of the substrate (38) surrounding the device (36) to form a cantilevered substrate platform (46) at which the MEMS device (36) resides. The cap layer (34) is coupled to the substrate (38) overlying the MEMS device (36). The MEMS die (22) is electrically interconnected with the IC die (24). Molding compound (32) is applied to substantially encapsulate the MEMS die (22), the IC die (24), and interconnects (30) that electrically interconnect the MEMS device (22) with the IC die (24). The cap layer (34) prevents the molding compound (32) from contacting the MEMS device (36).

Abstract: In a power semiconductor device and a method of forming a power semiconductor device, a thin layer of semiconductor substrate is left below the drift region of a semiconductor device. A power semiconductor device has an active region that includes the drift region and has top and bottom surfaces formed in a layer provided on a semiconductor substrate. A portion of the semiconductor substrate below the active region is removed to leave a thin layer of semiconductor substrate below the drift region. Electrical terminals are provided directly or indirectly to the top surface of the active region to allow a voltage to be applied laterally across the drift region.