Abstract: An infrared detector and a method for manufacturing it are disclosed. The infrared detector contains an absorber layer responsive to infrared light, a barrier layer disposed on the absorber layer, a plurality of contact structures disposed on the barrier layer; and an oxide layer disposed above the barrier layer and between the plurality of the contact structures, wherein the oxide layer reduces the dark current in the infrared detector. The method disclosed teaches how to manufacture the infrared detector.

Abstract: The present invention relates to a Hall effect sensor which is integrated in a semiconductor substrate and enables measurement of a magnetic field component. perpendicularly to the surface of the semiconductor substrate. The Hall effect sensor comprises several Hall elements having an electrically conductive semiconductor region which has a straight-line row of electrical measuring and control contacts on an end face on the substrate surface. The Hall elements are designed or can be operated in such manner that they have a sensitivity both to a magnetic field component parallel to and the magnetic field component perpendicular to the substrate surface of the semiconductor substrate (1). Several of the Hall elements are arranged such that their sensitivity to a magnetic field component parallel to the substrate surface of the semiconductor substrate can be compensated mutually by circuitry or in a signal evaluation.

Abstract: In one embodiment, an overvoltage protection device may include a semiconductor substrate comprising an n-type body region. The overvoltage protection device may further include a first p-type region disposed in a first surface region of the semiconductor substrate, and forming a first P/N junction with the n-type body region, and a second p-type region disposed in a second surface region of the semiconductor substrate opposite the first surface, and forming a second P/N junction with the n-type body region, wherein the n-type body region, first p-type region, and second p-type region form a breakdown device having a breakdown voltage greater than 100V when an external voltage is applied between the first surface region and second surface region.

Abstract: A Bipolar Junction Transistor with an intrinsic base, wherein the intrinsic base includes a top surface and two side walls orthogonal to the top surface, and a base contact electrically coupled to the side walls of the intrinsic base. In one embodiment an apparatus can include a plurality of Bipolar Junction Transistors, and a base contact electrically coupled to the side walls of the intrinsic bases of each BJT.

Abstract: A semiconductor structure and a method for manufacturing the same are provided. The method comprises following steps. A first silicon-containing conductive material is formed on a substrate. A second silicon-containing conductive material is formed on the first silicon-containing conductive material. The first silicon-containing conductive material and the second silicon-containing conductive material have different dopant conditions. The first silicon-containing conductive material and the second silicon-containing conductive material are thermally oxidized for turning the first silicon-containing conductive material wholly into an insulating oxide structure, and the second silicon-containing conductive material into a silicon-containing conductive structure and an insulating oxide layer.

Abstract: Some embodiments include apparatus and methods having a base; a memory cell including a body, a source, and a drain; and an insulation material electrically isolating the body, the source, and the drain from the base, where the body is configured to store information. The base and the body include bulk semiconductor material. Additional apparatus and methods are described.

Abstract: A design structure is embodied in a machine readable medium for designing, manufacturing, or testing a design. The design structure includes a structure which comprises a high-leakage dielectric formed in a divot on each side of a segmented FET comprised of active silicon islands and gate electrodes thereon, and a low-leakage dielectric on the surface of the active silicon islands, adjacent the high-leakage dielectric, wherein the low-leakage dielectric has a lower leakage than the high-leakage dielectric. Also provided is a structure and method of fabricating the structure.

Abstract: A semiconductor device has an active region formed on a semiconductor substrate, a trench-type element isolation region formed on the semiconductor substrate, and a diffusion region in which fluorine is diffused that surrounds the element isolation region and is formed on the semiconductor substrate so as not to contact the active region.

Abstract: A photovoltaic (PV) cell device comprises a first semiconductor substrate; a second semiconductor substrate bonded to the first semiconductor substrate; an insulating layer provided between the first and second substrates to electrically isolate the first substrate from the second substrate; a plurality of PV cells defined on the first substrate, each PV cell including a n-type region and a p-type region; a plurality of vertical trenches provided in the first substrate to separated the PV cells, the vertical trenches terminating at the insulating layer; a plurality of isolation structures provided within the vertical trenches, each isolation structure including a first isolation layer including oxide and a second isolation layer including polysilicon; and an interconnect layer patterned to connect the PV cells to provide X number of PV cells in series and Y number of PV cells in parallel.

Abstract: A semiconductor device structure includes a first type region and a second type region defined in a substrate, the first type region and second type region separated by one or more inter-well shallow trench isolation (STI) structures. At least one of the first type region and the second type region has one or more intra-well STI structures formed therein for isolating semiconductor devices formed within a same polarity well. The inter-well STI structures are formed at a substantially same depth with respect to the intra-well STI structures. A main well region is formed such that a bottom of the main well region is disposed above a bottom of the inter-well and intra-well STI features. One or more deep well regions couple the main well regions otherwise isolated by the intra-well STI structures, wherein the deep well regions are spaced away from the inter-well STI structures.

Abstract: The invention provides a STI structure and a method for manufacturing the same. The STI includes a semiconductor substrate; a first trench formed on the upper surface of the semiconductor substrate and filled with an epitaxial layer, wherein the upper surface of the epitaxial layer is higher than that of the semiconductor substrate; and a second trench formed on the epitaxial layer and filled with a first dielectric layer, wherein the upper surface of the first dielectric layer is flush with that of the epitaxial layer, and the width of the second trench is smaller than that of the first trench. The invention reduces the influences of divots on performance of the semiconductor device.

Abstract: A semiconductor memory device includes a first active region, a second active region, a first element isolating region and a second element isolating region. The first active region is formed in a semiconductor substrate. The second active region is formed in the semiconductor substrate. The first element isolating region electrically separates the first active regions adjacent to each other. The second element isolating region electrically separates the second active regions adjacent to each other. An impurity concentration in a part of the second active region in contact with a side face of the second element isolating region is higher than that in the central part of the second active region, and a impurity concentration in a part of the first active region in contact with a side face of the first element isolating region is equal to that in the first active region.

Abstract: A wafer processing method having a step of reducing the thickness of a wafer in only a device forming area where semiconductor chips are formed by grinding and etching the back side of the wafer to thereby form a recess on the back side of the wafer. At the same time, an annular projection is formed around the recess to thereby ensure the rigidity of the wafer. Accordingly, handling in shifting the wafer from the back side recess forming step to a subsequent step of forming a back side rewiring layer can be performed safely and easily.

Abstract: A semiconductor device includes a sidewall oxide layer covering an inner wall of a trench, a nitride liner on the sidewall oxide layer and a gap-fill insulating layer filling the trench on the nitride liner. A first impurity doped oxide layer is provided at edge regions of both end portions of the sidewall oxide layer so as to extend from an entry of the trench adjacent to an upper surface of the substrate to the nitride liner. A dent filling insulating layer is provided on the nitride liner in the trench to protect a surface of the first impurity doped oxide layer. Related methods are also disclosed.

Abstract: In a method of fabricating a flash memory device, a semiconductor substrate includes a tunnel insulating layer and a charge storage layer formed in an active region and a trench formed in an isolation region. A first insulating layer is formed to fill a part of the trench. A second insulating layer is formed on the first insulating layer so that the trench is filled. The first and second insulating layers are removed such that the first and second insulating layers remain on sidewalls of the charge storage layer and on a part of the trench. A third insulating layer is formed on the first and second insulating layers so that a space defined by the charge storage layer is filled. The third insulating layer is removed so that a height of the third insulating layer is lowered.

Abstract: The invention includes semiconductor assemblies having two or more dies. An exemplary assembly has circuitry associated with a first die front side electrically connected to circuitry associated with a second die front side. The front side of the second die is adjacent a back side of the first die, and a through wafer interconnect extends through the first die. The through wafer interconnect includes a conductive liner within a via extending through the first die. The conductive liner narrows the via, and the narrowed via is filled with insulative material. The invention also includes methods of forming semiconductor assemblies having two or more dies; and includes electronic systems containing assemblies with two or more dies.

Abstract: A CMOS image sensor and a method for fabricating the same are disclosed, in which the boundary between an active region and a field region is not damaged by ion implantation. The method for fabricating a CMOS image sensor includes forming a trench in a first conductive type semiconductor substrate, forming a first conductive type heavily doped impurity ion region in the semiconductor substrate at both sides of the trench, forming a device isolation film by interposing an insulating film between the trench and the device isolation, sequentially forming a gate insulating film and a gate electrode on the semiconductor substrate, and forming a second conductive type impurity ion region for a photodiode in the semiconductor substrate between the gate electrode and the device isolation film.

Abstract: An anisotropic conductive sheet manufactured through improved manufacturing steps and a method of manufacturing the same. Conductive portions are unevenly arranged in a nonconductive elastomer having fluidity and serving as a matrix, the conductive portions highly densely containing the conductive particles having a specific gravity greater than that of the matrix component, the conductive particles are unevenly dispersed to form substantially nonconductive portions, and the conductive portions and the nonconductive portions are integrally cured to mold anisotropic conductive pieces. The anisotropic conductive pieces are so laminated that the conductive portions and the nonconductive portions are alternately arranged thereby to obtain a first laminate, and the first laminate is cut maintaining a predetermined thickness to obtain a zebra-like sheet.

Abstract: To suppress occurrence of dislocation in a substrate of a semiconductor device at an end portion of a gate electrode. Provided is a semiconductor device having a plurality of element formation regions formed over the main surface of a semiconductor substrate, an element isolation trench located between the element formation regions and having an element isolation insulating film embedded therein, and a gate insulating film, a gate electrode and a plurality of interconnect layers formed thereabove, each formed in the element formation region, wherein the element isolation trench has a thermal oxide film formed between the semiconductor substrate and the element isolation insulating film, and the element isolation film has a great number of micro-pores formed inside thereof and is more porous than the thermal oxide film.

Abstract: A semiconductor device comprises a substrate. In addition, the semiconductor device comprises an active region and an isolation region. The active region is in the substrate and comprises a semiconductor material. The isolation region is also in the substrate, adjacent the active region and comprises an insulating material. The active region and isolation region form a surface having a step therein. The semiconductor further comprises a dielectric material formed over the step. The dielectric material has a dielectric constant greater than about 8.

Abstract: An integrated circuit device comprising: a body of a first solid material having an upper surface and a major bottom surface; a pocket of a second solid material having a top surface and a side surface, and a bottom surface which contacts a selected portion of said upper surface on said body; said first and second solid materials being so selected as to form, where said pocket contacts said body at said selected portion of said upper surface, an electronic interfacial barrier which is substantially conductive under an applied bias of at least one selected polarity; and a solid electrically insulating region which meets said barrier and adjoins both said body and at least a line on said side surface of said pocket; wherein at least a part of said solid electrically insulating region comprises nitrogen located at least below the level of said electronic interfacial barrier.

Abstract: An electro-mechanical system, the system comprising a first surface with an electrically activated electrode coupled to the first surface and to an electrical source to receive a first signal. The system further comprising a moveable structure suspended at a first height over the first surface, the moveable structure being attracted toward the electrode based upon the first signal, and the moveable structure being attracted toward the first surface through an interaction with one or more parasitic forces. The systems also provides a landing post coupled to the moveable structure, the landing post being adapted to contact the base of the landing post against the first surface when the electrically activated electrode receives a predetermined voltage bias associated with the first signal, thereby maintaining an outer portion of the moveable structure free from physical contact with the first surface and reducing a magnitude of one or more parasitic forces.

Abstract: A semiconductor device includes a region of semiconductor material with first and second isolation trenches formed therein. The first isolation trench is lined with a first material having a low oxygen diffusion rate and is filled with an insulating material. The second isolation trench is not lined with the first material but is filled with an insulating material. A first transistor is formed adjacent the first isolation region and a second transistor formed adjacent the second isolation region.

Abstract: Integrated circuit devices including an isolation region are provided. The devices include an integrated circuit substrate and a trench in the integrated circuit substrate that defines an active region of the integrated circuit device. A silicon layer is provided on the integrated circuit substrate that extends over an edge of the trench and along an upper portion of a first sidewall of the trench. An insulating material is positioned adjacent the silicon layer that extends across some, or all, of the trench to define the isolation region. Methods of forming such integrated circuit devices are also provided.

Abstract: A semiconductor device includes a transistor junction formed in a substrate adjacent to an isolation region. A region between the transistor junction and the isolation region includes an area susceptible to hot carrier effects. The transistor junction extends from a surface of the substrate to a first depth. A buried conductive channel layer is formed within the transistor junction between the surface of the substrate and the first depth. The buried conductive channel layer has a peak conduction depth, which is different from a depth of the area susceptible to hot carrier effects.

Abstract: The forming of a contact with a deep region of a first conductivity type formed in a silicon substrate. The contact includes a doped silicon well region of the first conductivity type and an intermediary region connected between the deep layer and the well. This intermediary connection region is located under a trench. The manufacturing method enables forming of vertical devices, in particular fast bipolar transistors.

Abstract: A semiconductor device includes a region of semiconductor material with first and second isolation trenches formed therein. The first isolation trench is lined with a first material having a low oxygen diffusion rate and is filled with an insulating material. The second isolation trench is not lined with the first material but is filled with an insulating material. A first transistor is formed adjacent the first isolation region and a second transistor formed adjacent the second isolation region.

Abstract: A microfabricated device includes a substrate having a device layer and substantially filled, isolating trenches; a doped region of material formed by photolithographically defining a region for selective doping of said device layer, selectively doping said region, and thermally diffusing said dopant; circuits on said device layer formed using a substantially standard circuit technology; and at least one structure trench in the substrate which completes the definition of electrically isolated micromechanical structural elements.

Abstract: A semiconductor transistor formed between trench device isolation regions comprises; a gate electrode formed on a device formation region with the intervention of a gate insulating film and extended over the trench device isolation regions, a distance from an interface between the gate electrode and the gate insulating film to the surface of the device formation region and a distance from said interface to the trench device isolation region being the same, and a gate electrode wiring formed in self-alignment with the gate electrode to have the same length as the length of the gate electrode and connected on the gate electrode on the device formation region.

Abstract: The present invention relates to a highly integrated SOI semiconductor device and a method for fabricating the SOI semiconductor device by reducing a distance between diodes or well resistors without any reduction in insulating characteristics. The device includes a first conductivity type semiconductor substrate and a surface silicon layer formed by inserting an insulating layer on the semiconductor substrate. A trench is formed by etching a predetermined portion of surface silicon layer, insulating layer and substrate to expose a part of the semiconductor substrate to be used for an element separating region, and a STI is formed in the trench. A transistor is constructed on the surface silicon layer surrounded by the insulating layer and STI with a gate electrode being positioned at the center thereof and with source/drain region being formed in the surface silicon layer of both edges of the gate electrode for enabling its bottom part to be in contact with the insulating layer.

Abstract: Integrated circuit devices including an isolation region are provided. The devices include an integrated circuit substrate and a trench in the integrated circuit substrate that defines an active region of the integrated circuit device. A silicon layer is provided on the integrated circuit substrate that extends over an edge of the trench and along an upper portion of a first sidewall of the trench. An insulating material is positioned adjacent the silicon layer that extends across some, or all, of the trench to define the isolation region. Methods of forming such integrated circuit devices are also provided.

Abstract: A semiconductor device and a method for fabricating the same are provided. The provided semiconductor device includes a field oxide layer formed in a semiconductor substrate to define an active region; gate structures formed on the active region; source/drain junctions formed on either side of the gate structures on the semiconductor substrate; a channel silicon layer arranged under the gate insulating layer to operate as a channel for connecting sources and drains; and buried junction isolation insulating layers under the channel silicon layer. The buried junction isolation insulating layers isolate source/drain junction regions of a MOS transistor, so that a short circuit in a bulk region under the channel of a transistor due to the high-integration of the device can be prevented.

Abstract: A semiconductor device in which the potential of a conductive support substrate can be kept to be a predetermined potential, while an SOI substrate is used as a chip substrate, without adding a new step and providing a rear electrode, is provided. In a chip, on the main surface of a first Si substrate of a P-type, a SiO2 film and a second Si substrate of a P-type are laminated in this order. The chip has, in the second Si substrate, isolation trenches, an outermost isolation trench, a plurality of element forming regions isolated by these trenches, second element forming regions, a peripheral region, and a peripheral region connection wiring which connects a contact region of the peripheral region with a contact region connected with a predetermined potential, for example, a ground potential in the second element forming region surrounded by, for example, the isolation trench.

Abstract: In order that the yield can be enhanced, the method of manufacturing a semiconductor device comprises the steps of: forming first holes 101a not penetrating a support side silicon wafer 101; forming a ground insulating film 102; forming primary connection plugs 105a by charging copper into the first holes 101a; forming a semiconductor film 108 on one face side of the support side silicon wafer 101 through an intermediate insulating film 109; forming elements on the semiconductor film 108; exposing bottom faces of the primary connection plugs 105a by polishing the other face of the support side silicon wafer 101; forming second holes 111 extending from an element forming face of the semiconductor film 108 to the primary connection plugs 105; and forming auxiliary connection plugs 112a for electrically connecting the elements with the primary connection plugs 105a by charging copper into the second holes 111.

Abstract: Existing polysilicon emitter technology is used to contact poly fill in a trench isolation structure. A standard single poly emitter window process is followed. An “emitter window” is masked directly over the polysilicon trench fill. Heavily doped single emitter poly is deposited and masked over the entire active region. The standard emitter drive then diffuses dopant through the emitter window into the undoped trench poly fill to provide an ohmic contact between the emitter poly and the trench poly fill. Contact to the emitter poly is made from overlying metal.

Abstract: A trenched field effect transistor is provided that includes (a) a semiconductor substrate, (b) a trench extending a predetermined depth into the semiconductor substrate, (c) a pair of doped source junctions, positioned on opposite sides of the trench, (d) a doped heavy body positioned adjacent each source junction on the opposite side of the source junction from the trench, the deepest portion of the heavy body extending less deeply into said semiconductor substrate than the predetermined depth of the trench, and (e) a doped well surrounding the heavy body beneath the heavy body.

Abstract: A method and structure for selectively growing epitaxial silicon in a trench formed within a silicon-on-insulator (SOI) structure. The SOI structure includes a buried oxide layer (BOX) on a bulk silicon substrate, and a silicon layer on the BOX. A pad layer is formed on the silicon layer. The pad layer includes a pad nitride (e.g., silicon nitride) on a pad oxide (e.g., silicon dioxide), and the pad oxide has been formed on the silicon layer. A trench is formed by anisotropically etching through the pad layer, the silicon layer, the BOX, and to a depth within the bulk silicon substrate. Insulative spacers are formed on sidewalls of the trench. An epitaxial silicon layer is grown in the trench from a bottom of the trench to above the pad layer. The pad layer and portions of the epitaxial layer are removed (e.g., by chemical mechanical polishing), resulting in a planarized top surface of the epitaxial layer that is about coplanar with a top surface of the silicon layer.

Abstract: An image sensor capable of preventing the degradation of pinned photodiodes and the generation of leakage current between neighboring pinned photodiodes is provided. The disclosed image sensor contains a plurality of pixel units, each pixel unit having a photodiode region. The image sensor includes a semiconductor substrate of a first conductivity type; a device isolation layer formed in the semiconductor substrate; a field stop layer formed beneath the device isolation layer; a trench formed in the semiconductor substrate, wherein the trench surrounds the photodiode region; a first doping region of the first conductivity type formed beneath the surface of the semiconductor substrate and beneath the surfaces of the trench; an insulating member filling the trench; and a second doping region of a second conductivity type formed in the semiconductor substrate under the first doping region.

Abstract: A semiconductor projection is formed on a semiconductor substrate of the first conductivity type and has a semiconductor layer of the first conductivity type. The semiconductor projection has a top surface and side surfaces. A gate electrode is formed above at least the side surfaces of the semiconductor projection. Source and drain regions are formed in the side surfaces of the semiconductor projection on opposite sides of the gate electrode. First and second device isolation insulating films are formed on the semiconductor substrate on opposite sides of the semiconductor projection. A first impurity region is formed in the semiconductor substrate below the first device isolation insulating film. A second impurity region is formed in the semiconductor substrate below the second device isolation insulating film. The first and second impurity regions are in contact with each other in the semiconductor substrate below the semiconductor projection.

Abstract: The number of design processes for fabricating semiconductor devices can be reduced by parallel connection of a plurality of unit bipolar transistors Qu that are completely electrically isolated from each other in a semiconductor layer of an SOI substrate 1 to form a bipolar transistor having a large current capacity.

Abstract: A reduced device geometry semiconductor memory device is provided which has increased device efficiency because of an increased gate coupling coefficient. Shallow trench isolations are formed in a semiconductor substrate. The shallow trench isolations are selectively shaped in order to form a control gate dielectric layer later with a large width relative to the width between the floating gates.

Abstract: A semiconductor device having a self-aligned contact pad and the method for manufacturing the device are disclosed. The semiconductor device includes: an isolation region formed in a semiconductor substrate; multiple conductive structures formed on the top surface of the semiconductor substrate; self-aligned conductive pads filling spaces between adjacent conductive structures and between the isolation region and the conductive structures. The method includes: forming a conductive structure on a semiconductor substrate; forming insulating sidewall spacers on the conductive structures, forming a conductive layer that fills spaces between the conductive structures and contacts the semiconductor substrate; and patterning the conductive layer.

Abstract: A microelectronic device includes a field oxide isolation pad which extends from a trench formed in a microelectronic substrate by a height which is less than approximately two times the height of a gate structure formed on the microelectronic substrate. Spacers are formed around the gate structures, although little or no spacer forms around the isolation pad.

Abstract: The invention relates to semiconductor devices having a bipolar transistor to form an isolation area within a base electrode contact area to ensure stable contact of the base electrode. The bipolar transistor formed in the transistor area is in the form of an island and is rectangular when view from above. The isolation area is formed of a dielectric material around the transistor area, and the base area is formed around the emitter area which forms the central area of the transistor area. A contact groove is formed at the inner interface of the isolation groove which faces the outer surface of the transistor area, and a part of the base electrode is buried in the contact groove and faces at least one of the upper surface of the transistor area and an inner surface of the contact groove.

Abstract: By improving profile of impurity concentration in a channel portion of an FET or an IGBT of a trench gate type, variation of threshold value is lessened, and a destruction caused by current concentration is prevented while suppressing deterioration of cut-off characteristics. An island of a base region of p-type is formed in a semiconductor substrate of n-type by carrying out high acceleration ion implantation twice followed by annealing, so that the impurity concentration profile in a channel portion changes gradually in a depth direction. Accordingly, it is possible to lessen variation of the threshold value and to reduce pinch resistance while at the same time improving sub-threshold voltage coefficient and conductance characteristics.

Abstract: Source and drain regions of field effect transistors are fabricated with an electrically insulating layer formed thereunder so as to reduce junction capacitance between each and a semiconductor body in which the regions are formed. Shallow trench isolation partially surrounds each transistor so as to further electrically isolate the source and drain regions from the semiconductor body. Typically for a single transistor only one surface of each drain and source region make direct contact to the semiconductor body and these surfaces are on opposite sides of a channel region of each transistor. One method of fabrication of the source and drain regions is to form an isolating isolation region around active areas in which a transistor is to be formed in a semiconductor body. Trenches separated by portions of the body are then formed in the active areas in which transistors are to be formed. On bottom surfaces of the trenches are formed an electrically insulating layer.

Abstract: A bipolar transistor is vertically isolated from underlying silicon by an isolation layer of conductivity type opposite that of the collector. This isolation layer lies beneath the heavily doped buried layer portion of the collector, and is formed either by ion implantation prior to epitaxial growth of well regions, or by high energy ion implantation into the substrate prior to formation of the well and the heavily doped buried collector layer. Utilization of trench lateral isolation extending into the semiconductor material beyond the isolation layer permits blanket implant of the isolation layer, obviating the need for an additional masking step.

Abstract: A semiconductor device includes an n-channel MOSFET isolated by an element isolation region of STI structure. A silicon nitride (SiN) region is formed in an Si substrate near the interface between the element isolation region and the Si substrate. The silicon nitride region is formed by ion-implanting nitrogen (N) into the Si substrate. The silicon nitride region is acts as a barrier layer for preventing substrate impurity of the n-channel MOSFET (impurity contained in the channel region) from being thermally diffused into the element isolation region. The silicon nitride region is distributed from the main surface of the Si substrate in the end portion of the element isolation region to a region deeper than the substrate depth which determines the threshold voltage of the MOSFET.

Abstract: A nonvolatile semiconductor memory has memory cells (1) each having an insulated-gate FET that has an information storage part. A semiconductor region (27) is formed at the surface of a channel region of each memory cell. The semiconductor region has the same conductivity type as a channel conductivity type and functions to decrease the strength of an electric field at the surface of the channel region. If the insulated-gate FET is of an n-channel type, the semiconductor region is of an n-type. The semiconductor region suppresses threshold voltage variations among the insulated-gate FETs of the memory cells and prevents soft-writing in the memory cells.

Abstract: A method and structure for improving the latch-up characteristic of semiconductor devices is provided. A dual depth STI is used to isolate the wells from each other. The trench has a first substantially horizontal surface at a first depth and a second substantially horizontal surface at a second depth which is deeper than the first depth. The n- and p-wells are formed on either side of the trench. A highly doped region is formed in the substrate underneath the second substantially horizontal surface of the trench. The highly doped region abuts both the first and the second wells and extends the isolation of the trench.