Abstract: An integrated circuit including a Schottky diode, and a method of making the same. The diode includes an active region bordered by an isolation region in a semiconductor substrate of the integrated circuits, a first electrode having a metal contact provided on a surface of the active region, and a second electrode having a silicide contact also provided on the surface of the active region.

Abstract: A Schottky diode device is provided, including a p-type semiconductor structure. An n drift region is disposed over the p-type semiconductor structure, wherein the n drift region comprises first and second n-type doping regions having different n-type doping concentrations, and the second n-type doping region is formed with a dopant concentration greater than that in the first n-type doping region. A plurality of isolation structures is disposed in the second n-type doping region of the n drift region, defining an anode region and a cathode region. A third n-type doping region is disposed in the second n-type doping region exposed by the cathode region. An anode electrode is disposed over the first n-type doping region in the anode region. A cathode electrode is disposed over the third n-type doping region in the cathode region.

Abstract: To provide a Schottky electrode in a diamond semiconductor, which has a good adhesion properties to diamonds, has a contacting surface which does not become peeled due to an irregularity in an external mechanical pressure, does not cause a reduction in yield in a diode forming process and does not cause deterioration in current-voltage characteristics, and a method of manufacturing the Schottky electrode. A Schottky electrode which includes: scattered island-form pattern Pt-group alloy thin films which are formed on a diamond surface formed on a substrate, in which the Pt-group alloy includes 50 to 99.9 mass % of Pt and 0.

Abstract: A semiconductor device has a trench junction barrier Schottky diode that includes an integrated substrate p-n diode (TJBS-Sub-PN) as a clamping element, the trench junction barrier Schottky diode being suited, e.g., as a Zener diode having a breakdown voltage of approximately 20 V, for use in motor-vehicle generator systems. In this context, the TJBS-Sub-PN is made up of a combination of a Schottky diode, an epitaxial p-n diode and a substrate p-n diode, and the breakdown voltage of the substrate p-n diode (BV_pn) is less than the breakdown voltage of the Schottky diode (BV_schottky) and the breakdown voltage of the epitaxial p-n diode (BV_epi).

Abstract: A nonvolatile memory element comprises a resistance variable element 105 configured to reversibly change between a low-resistance state and a high-resistance state in response to electric signals with different polarities which are applied thereto; and a current controlling element 112 configured such that when a current flowing when a voltage whose absolute value is a first value as a desired value which is larger than 0 and smaller than a predetermined voltage value and whose polarity is a first polarity is applied is a first current and a current flowing when a voltage whose absolute value is the first value and whose polarity is a second polarity different from the first polarity is applied is a second current, the first current is higher than the second current, and the resistance variable element is connected in series with the current controlling element such that a polarity of a voltage applied to the current controlling element when the resistance variable element is changed from the low-resistance s

Abstract: A switching element that includes a first semiconductor layer, the first semiconductor layer having a first portion and a second portion; a second semiconductor layer, the second semiconductor layer having a first portion and a second portion; an insulating layer disposed between the first semiconductor layer and the second semiconductor layer; a first metal contact in contact with the first portion of the first semiconductor layer forming a first junction and in contact with the first portion of the second semiconductor layer forming a second junction; a second metal contact in contact with the second portion of the first semiconductor layer forming a third junction and in contact with the second portion of the second semiconductor layer forming a fourth junction, wherein the first junction and the fourth junction are Schottky contacts, and the second junction and the third junction are ohmic contacts.

Abstract: A schottky diode includes a drift region of a first conductivity type and a lightly doped silicon region of the first conductivity type in the drift region. A conductor layer is over and in contact with the lightly doped silicon region to form a schottky contact with the lightly doped silicon region. A highly doped silicon region of the first conductivity type is in the drift region and is laterally spaced from the lightly doped silicon region such that upon biasing the schottky diode in a conducting state, a current flows laterally between the lightly doped silicon region and the highly doped silicon region through the drift region. A plurality of trenches extend into the drift region perpendicular to the current flow. Each trench has a dielectric layer lining at least a portion of the trench sidewalls and at least one conductive electrode.

Abstract: A method of manufacturing a semiconductor device is disclosed. The method includes forming a first trench and a second trench in an n-type substrate surface, the first trenches being spaced apart from each other, the second trench surrounding the first trenches, the second trench being wider than the first trench. The method also includes forming a gate oxide film on the inner surfaces of the first and second trenches, and depositing an electrically conductive material to the thickness a half or more as large as the first trench width. The method further includes removing the electrically conductive material using the gate oxide film as a stopper layer, forming an insulator film thicker than the gate oxide film, and polishing the insulator film by CMP for exposing the n-type substrate and the electrically conductive material in the first trench.

Abstract: The present disclosure relates to forming multi-layered contact pads for a semiconductor device, wherein the various layers of the contact pad are formed using one or more thin-film deposition processes, such as an evaporation process. Each contact pad includes an adhesion layer, which is formed over the device structure for the semiconductor device; a titanium nitride (TiN) barrier layer, which is formed over the adhesion layer; and an overlay layer, which is formed over the barrier layer. At least the titanium nitride (TiN) barrier layer is formed using an evaporation process.

Abstract: In one embodiment, a Schottky diode is formed on a semiconductor substrate with other semiconductor devices and is also formed with a high breakdown voltage and a low forward resistance.

Abstract: A semiconductor rectifier includes a semiconductor substrate having a first type of conductivity. A first layer, which is formed on the substrate, has the first type of conductivity and is more lightly doped than the substrate. A second layer having a second type of conductivity is formed on the substrate and a metal layer is disposed over the second layer. The second layer is lightly doped so that a Schottky contact is formed between the metal layer and the second layer. A first electrode is formed over the metal layer and a second electrode is formed on a backside of the substrate.

Abstract: First and second synthetic diamond regions are doped with boron. The second synthetic diamond region is doped with boron to a greater degree than the first synthetic diamond region, and in physical contact with the first synthetic diamond region. In a further example embodiment, the first and second synthetic diamond regions form a diamond semiconductor, such as a Schottky diode when attached to at least one metallic lead.

Abstract: In a pn junction diode having a conductivity modulating element provided on a first principal surface of a semiconductor substrate, when an impurity concentration of a p type impurity region is lowered to shorten a reverse recovery time, hole injection is suppressed, thereby causing a problem that a forward voltage value is increased at a certain current point. Moreover, introduction of a life time killer to shorten the reverse recovery time leads to a problem of increased leak current. On an n? type semiconductor layer that is a single crystal silicon layer, a p type polycrystalline silicon layer (p type polysilicon layer) is provided. Since the polysilicon layer has more grain boundaries than the single crystal silicon layer, an amount of holes injected into the n? type semiconductor layer from the p type polysilicon layer in forward voltage application can be suppressed.

Abstract: An optical device includes a first electrode of a first conductivity type, and a second electrode of a second conductivity type. A nanowire is positioned between the first and second electrodes. The nanowire has at least two segments and a junction region formed between the at least two segments. One of the segments is the first conductivity type and the other of the segments is the second conductivity type. At least one of the at least two segments has a predetermined characteristic that affects optical behavior of the junction region.

Abstract: A non-volatile semiconductor storage device includes a plurality of memory element groups, each of the memory element groups having a plurality of memory elements, each of the memory elements having a resistance-change element and a Schottky diode connected in series. Each of the memory element groups includes: a first columnar layer extending in a lamination direction; a first insulation layer formed on a side surface of the first columnar layer and functioning as the resistance-change element; and a first conductive layer formed to surround the first columnar layer via the first insulation layer. The first conductive layer is formed of metal. The first columnar layer is formed of a semiconductor having such a impurity concentration that the first conductive layer and the semiconductor configure the Schottky diode.

Abstract: The present invention discloses a Schottky diode. The Schottky diode comprises a cathode region, an anode region and a guard ring region. The anode region may comprise a metal Schottky contact. The guard ring region may comprise an outer guard ring and a plurality of inner guard stripes inside the outer guard ring. And wherein the inner guard stripe has a shallower junction depth than the outer guard ring.

Abstract: An integrated circuit, including a junction barrier Schottky diode, has an N type well, a P-type anode region in the surface of the well, and an N-type Schottky region in the surface of the well and horizontally abutting the anode region. A first silicide layer is on and makes a Schottky contact to the Schottky region and is on an adjoining anode region. A second silicide layer of a different material than the first silicide is on the anode region. An ohmic contact is made to the second silicide on the anode region and to the well.

Abstract: A device according to the invention comprises a Schottky barrier formed by a metal-semiconductor junction between a semiconductor nanowire (1) and a metal contact (5). The metal contact (5) at least partly encloses a circumferential area of each nanowire (1) along the length thereof. The nanowire (2) comprises a lowly doped region that is part of the metal-semiconductor junction. This lowly doped region can be formed by a nanowire segment, by the entire nanowire or in a core-shell configuration with a highly doped nanowire core (3) and the lowly doped region comprised in a shell (4). The device can be fabricated using a method according to the invention, where two different growth modes are used, the first comprising axial growth from a substrate (2) giving a suitable template for formation of the metal-semiconductor junction and the second step comprising radial growth enabling control of the doping levels in the lowly doped region.

Abstract: A method for formation of a segregated interfacial dopant layer at a junction between a semiconductor material and a silicide layer includes depositing a doped metal layer over the semiconductor material; annealing the doped metal layer and the semiconductor material, wherein the anneal causes a portion of the doped metal layer and a portion of the semiconductor material to react to form the silicide layer on the semiconductor material, and wherein the anneal further causes the segregated interfacial dopant layer to form between the semiconductor material and the silicide layer, the segregated interfacial dopant layer comprising dopants from the doped metal layer; and removing an unreacted portion of the doped metal layer from the silicide layer.

Abstract: A Schottky diode comprising a merged guard ring and field plate defining a Schottky contact region is provided. A Schottky metal is formed over at least partially over the Schottky contact region and at least partially over the merged guard ring and field plate.

Abstract: A CMOS device and method of manufacture is provided for producing an integrated circuit that is not susceptible to various soft errors such as single-event upsets, multi-bit upsets or single-event latchup. The CMOS device and method utilizes a new and novel well architecture in conjunction with metal source/drain electrodes to eliminate soft errors. In one embodiment, the CMOS device uses a first metal source/drain material for the NMOS device and a second metal source/drain material for the PMOS device. The CMOS device further uses a multi-layered well-structure with a shallow N-well and a buried P-well for the PMOS device and a shallow P-well and a buried N-well for the NMOS device.

Abstract: A semiconductor substrate and a method of its manufacture has a semiconductor substrate having a carbon concentration in a range of 6.0×1015 to 2.0×1017 atoms/cm3, both inclusively. One principal surface of the substrate is irradiated with protons and then heat-treated to thereby form a broad buffer structure, namely a region in a first semiconductor layer where a net impurity doping concentration is locally maximized. Due to the broad buffer structure, lifetime values are substantially equalized in a region extending from an interface between the first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer to the region where the net impurity doping concentration is locally maximized. In addition, the local minimum of lifetime values of the first semiconductor layer becomes high.

Abstract: A resistive memory structure, for example, phase change memory structure, includes one access device and two or more resistive memory cells. Each memory cell is coupled to a rectifying device to prevent parallel leak current from flowing through non-selected memory cells. In an array of resistive memory bit structures, resistive memory cells from different memory bit structures are stacked and share rectifying devices.

Abstract: A manufacturing method for a silicon carbide semiconductor device is disclosed. It includes an etching method in which an Al film and Ni film are laid on an SiC wafer in this order and wet-etched, whereby a two-layer etching mask is formed in which Ni film portions overhang Al film portions. Mesa grooves are formed by dry etching by using this etching mask.

Abstract: This invention discloses a bottom-anode Schottky (BAS) diode that includes an anode electrode disposed on a bottom surface of a semiconductor substrate. The bottom-anode Schottky diode further includes a sinker dopant region disposed at a depth in the semiconductor substrate extending substantially to the anode electrode disposed on the bottom surface of the semiconductor and the sinker dopant region covered by a buried Schottky barrier metal functioning as a Schottky anode.

Abstract: A monolithic semiconductor structure includes a stack of layers. The stack includes a substrate; a first layer made from a first semiconductor material; and a second layer made from a second semiconductor material. The first layer is situated between the substrate and the second layer and at least one of the first semiconductor material and the second semiconductor material contains a III-nitride material. The structure includes a power transistor, including a body formed in the stack of layers; a first power terminal at a side of the first layer facing the second layer; a second power terminal at least partly formed in the substrate; and a gate structure for controlling the propagation through the body of electric signals between the first power terminal and the second power terminal.

Abstract: A method for forming a metal-semiconductor Schottky contact in a well region is provided. The method includes forming a first insulating layer overlying a shallow trench isolation in the well region; and removing a portion of the first insulating layer such that only the well region and a portion of the shallow trench isolation is covered by a remaining portion of the first insulating layer. The method further includes forming a second insulating layer overlying the remaining portion of the first insulating layer and using a contact mask, forming a contact opening in the second insulating layer and the remaining portion of the first insulating layer to expose a portion of the well region. The method further includes forming the metal-semiconductor Schottky contact in the exposed portion of the well region by forming a metal layer in the contact opening and annealing the metal layer.

Abstract: A gate after diamond transistor and method of making comprising the steps of depositing a first dielectric layer on a semiconductor substrate, depositing a diamond particle nucleation layer on the first dielectric layer, growing a diamond thin film layer on the first dielectric layer, defining an opening for the gate in the diamond thin film layer, patterning of the diamond thin film layer for a gate metal to first dielectric layer surface, etching the first dielectric layer, depositing and defining a gate metal, and forming a contact window opening in the diamond thin film layer and the first dielectric layer to the ohmic contact.

Abstract: A process for forming a trench Schottky barrier device includes the forming of an oxide layer within the trenches in the surface of a silicon wafer, and then depositing a full continuous metal barrier layer over the full upper surface of the wafer including the trench interiors and the mesas between trenches with a barrier contact made to the mesas only. Palladium, titanium or any conventional barrier metal can be used.

Abstract: A schottky diode includes a SiC substrate which has a first surface and a second surface facing away from the first surface, a semiconductor layer which is formed on the first surface of the SiC substrate, a schottky electrode which is in contact with the semiconductor layer, and an ohmic electrode which is in contact with the second surface of the SiC substrate. The first surface of the SiC substrate is a (000-1) C surface, upon which the semiconductor layer is formed.

Abstract: A semiconductor device includes a semiconductor layer having a first conductivity type and having a surface in which an active region of the semiconductor device is defined, and a plurality of spaced apart doped regions within the active region. The plurality of doped regions have a second conductivity type that is opposite the first conductivity type and define a plurality of exposed portions of the semiconductor layer within the active region. The plurality of doped regions include a plurality of rows extending in a longitudinal direction. Each of the rows includes a plurality of longitudinally extending segments, and the longitudinally extending segments in a first row at least partially overlap the longitudinally extending segments in an adjacent row in a lateral direction that is perpendicular to the longitudinal direction.

Abstract: To fabricate a Schottky barrier diode in which a decrease in on current due to parasitic resistance is suppressed, variations in on current are suppressed, and an increase in off current is suppressed. The fabricating method includes the steps of forming an island-shape semiconductor film; doping the island-shape semiconductor film with a first impurity element to form a first impurity region; forming an insulating film so as to cover the island-shape semiconductor film; etching the insulating film to form a first opening and a second opening that partly expose the first impurity region; forming a mask over the insulating film so as to cover the first opening and expose the second opening; doping the first impurity region with a second impurity element to form a second impurity region; and forming a first wiring in contact with the first impurity region exposed at the first opening, and forming a second wiring in contact with the second impurity region exposed at the second opening.

Abstract: A Schottky barrier diode comprises a doped guard ring having a doping of a second conductivity type in a semiconductor-on-insulator (SOI) substrate. The Schottky barrier diode further comprises a first-conductivity-type-doped semiconductor region having a doping of a first conductivity type, which is the opposite of the second conductivity type, on one side of a dummy gate electrode and a Schottky barrier structure surrounded by the doped guard ring on the other side. A Schottky barrier region may be laterally surrounded by the dummy gate electrode and the doped guard ring. The doped guard ring includes an unmetallized portion of a gate-side second-conductivity-type-doped semiconductor region having a doping of a second conductivity type. A Schottky barrier region may be laterally surrounded by a doped guard ring including a gate-side doped semiconductor region and a STI-side doped semiconductor region. Design structures for the inventive Schottky barrier diode are also provided.

Abstract: The present invention provides a semiconductor apparatus for improving a switching speed and a withstand voltage, and a manufacturing method of the semiconductor apparatus.

Abstract: A fabrication method of a trenched power semiconductor structure with a schottky diode is provided. Firstly, a drain region is formed in a substrate. Next, at least two gate structures are formed above the drain region, and then, a body and at least a source region are formed between the two adjacent gate structures. Thereafter, a first dielectric structure is formed on the gate structure to shield the gate structure. Then, a contact window is formed in the body and has side surface thereof adjacent to the source region to expose the source region. Afterward, a second dielectric structure is formed in the contact window. Next, by using the second dielectric structure as an etching mask, the body is etched to form a narrow trench extending to the drain region below the body. Finally, a metal layer is filled into the contact window and the narrow trench.

Abstract: Improved Schottky diodes with reduced leakage current and improved breakdown voltage are provided by building a JFET with its current path of a first conductivity type serially located between a first terminal comprising a Schottky contact and a second terminal. The current path lies (i) between multiple substantially parallel finger regions of a second, opposite, conductivity type substantially laterally outboard of the Schottky contact, and (ii) partly above a buried region of the second conductivity type that underlies a portion of the current path, which regions are electrically coupled to the first terminal and the Schottky contact and which portion is electrically coupled to the second terminal. When reverse bias is applied to the first terminal and Schottky contact the current path is substantially pinched off in vertical or horizontal directions or both, thereby reducing the leakage current and improving the breakdown voltage of the device.

Abstract: A schottky diode of the trench variety which includes a trench termination having a thick insulation layer that is thicker than the insulation layer inside the trenches in its active region.

Abstract: Methods of forming features and structures thereof are disclosed. In one embodiment, a method of forming a feature includes forming a first material over a workpiece, forming a first pattern for a lower portion of the feature in the first material, and filling the first pattern with a sacrificial material. A second material is formed over the first material and the sacrificial material, and a second pattern for an upper portion of the feature is formed in the second material. The sacrificial material is removed. The first pattern and the second pattern are filled with a third material.

Abstract: The present invention is directed to a diode with an asymmetric silicon germanium anode and methods of making same. In one illustrative embodiment, the diode includes an anode comprising a P-doped silicon germanium material formed in a semiconducting substrate, an N-doped silicon cathode formed in the semiconducting substrate, a first conductive contact that is conductively coupled to the anode and a second conductive contact that is conductively coupled to the cathode.

Abstract: Cobalt silicide (CoSi2) Schottky diodes fabricated per the current art suffer from excess leakage currents in reverse bias. In this invention, an floating p-type region encircles each anode of a CoSi2 Schottky diode comprising of one or more CoSi2 anodes. The resulting p-n junction forms a depletion region under the Schottky junction that reduces leakage current through the Schottky diodes in reverse bias operation.

Abstract: Methods and apparatus are described for semiconductor devices. A method comprises providing a partially completed semiconductor device including a substrate, a semiconductor on the substrate, and a passivation layer on the semiconductor, and using a first mask, locally etching the passivation layer to expose a portion of the semiconductor, and without removing the first mask, forming a Schottky contact of a first material on the exposed portion of the semiconductor, then removing the first mask, and using a further mask, forming a step-gate conductor of a second material electrically coupled to the Schottky contact and overlying parts of the passivation layer adjacent to the Schottky contact. By minimizing the process steps between opening the Schottky contact window in the passivation layer and forming the Schottky contact material in this window, the gate leakage of a resulting field effect device having a Schottky gate may be substantially reduced.

Abstract: A semiconductor device formed on a semiconductor substrate may include a component formed in a contact trench located in an active cell region. The component may comprise a barrier metal deposited on a bottom and portions of sidewalls of the contact trench and a tungsten plug deposited in a remaining portion of the contact trench. The barrier metal may comprise first and second metal layers. The first metal layer may be proximate to the sidewall and the bottom of the contact trench. The first metal layer may include a nitride. The second metal layer may be between the first metal layer and the tungsten plug and between the tungsten plug and the sidewall. The second metal layer covers portions of the sidewalls of not covered by the first metal layer.

Abstract: Provided is an optical device having a strained buried channel area. The optical device includes: a semiconductor substrate of a first conductive type; a gate insulating layer formed on the semiconductor substrate; a gate of a second conductive type opposite to the first conductive type, formed on the gate insulating layer; a high density dopant diffusion area formed in the semiconductor substrate under the gate and doped with a first conductive type dopant having a higher density than the semiconductor substrate; a strained buried channel area formed of a semiconductor material having a different lattice parameter from a material of which the semiconductor substrate is formed and extending between the gate insulating layer and the semiconductor substrate to contact the high density dopant diffusion area; and a semiconductor cap layer formed between the gate insulating layer and the strained buried channel area.

Abstract: A semiconductor device which may include a semiconductor layer, and a superlattice interface layer therebetween. The superlattice interface layer may include a plurality of stacked groups of layers. Each group of layers may include a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. At least some atoms from opposing base semiconductor portions may be chemically bound together with the chemical bonds traversing the at least one intervening non-semiconductor monolayer.

Abstract: A method for manufacturing a metal-semiconductor contact in semiconductor Components is disclosed. There is a relatively high risk of contamination in the course of metal depositions in prior-art methods. In the disclosed method, the actual metal -semiconductor or Schottky contact is produced only after the application of a protective layer system, as a result of which it is possible to use any metals, particularly platinum, without the risk of contamination.

Abstract: Fabrication of a Schottky diodes may include providing a Schottky contact layer containing a low barrier metal layer with spaced apart high barrier metal islands therein on a first surface of a substrate. A diode contact is formed on a second surface of the substrate that is opposite to the first surface. Formation of the Schottky contact layer may include providing a liquid mixture of a high barrier metal and a low barrier metal on the first surface of the substrate. Temperature and/or relative concentrations of the high and low barrier metals in the liquid mixture may be controlled to cause regions of the high barrier metal to solidify within the liquid mixture and agglomerate to form the spaced apart high barrier metal islands while inhibiting solidification of the low barrier metal. The temperature and relative concentrations may then be controlled to cause the low barrier metal to solidify and form the low barrier metal layer containing the high barrier metal islands.

Abstract: A method for manufacturing a compound semiconductor device forms an EB resist layer on first SiN film, performs EB exposure at high dose for recess forming opening and at low dose for eaves removing opening, develops the high dose EB resist pattern to etch the first SiN film, selectively etches the cap layer to form a recess wider than the opening of the first SiN film leaving eaves of SiN, develops the low dose EB resist pattern to form the eaves removing opening, etches the first SiN film to extinguish the eaves, forms second SiN film on the exposed surface, forms a resist pattern having a gate electrode opening on the second SiN film to etch the second SiN film, forms a metal layer to form a gate electrode by lift-off. The SiN film in eaves shape will not be left.

Abstract: A silicon carbide Schottky barrier semiconductor device provided with a Ta electrode as a Schottky electrode, in which the Schottky barrier height is controlled to a desired value in a range where power loss is minimized without increasing the n factor. The method for manufacturing the silicon carbide Schottky barrier semiconductor device includes the steps of depositing Ta on a crystal face of an n-type silicon carbide epitaxial film, the crystal face having an inclined angle in the range of 0° to 10° from a (000-1) C face, and carrying out a thermal treatment at a temperature range of 300 to 1200° C. to form the Schottky electrode.

Abstract: Provided is a method of fabricating a Schottky barrier transistor. The method includes (a) forming a pair of cavities for forming a source forming portion and a drain forming portion having a predetermined depth and parallel to each other and a channel forming portion having a fin shape between the cavities in a substrate; (b) filling the pair of cavities with a metal; (c) forming a channel, a source, and a drain by patterning the channel forming portion, the source forming portion, and the drain forming portion in a direction perpendicular to a lengthwise direction of the channel forming portion; (d) sequentially forming a gate oxide layer and a gate metal layer that cover the channel, the source, and the drain on the substrate; and (e) forming a gate electrode corresponding to the channel by patterning the gate metal layer, wherein one of the operations (b) through (e) further comprises forming a Schottky barrier by annealing the substrate.

Abstract: An embodiment of the invention is a Schottky diode 22 having a semiconductor substrate 3, a first metal 24, a barrier layer 26, and second metal 28. Another embodiment of the invention is a method of manufacturing a Schottky diode 22 that includes providing a semiconductor substrate 3, forming a barrier layer 26 over the semiconductor substrate 3, forming a first metal layer 23 over the semiconductor substrate 3, annealing the semiconductor substrate 3 to form areas 24 of reacted first metal and areas 23 of un-reacted first metal, and removing selected areas 23 of the un-reacted first metal. The method further includes forming a second metal layer 30 over the semiconductor substrate 3 and annealing the semiconductor substrate 3 to form areas 28 of reacted second metal and areas 30 of un-reacted second metal.