Abstract: An embodiment of an electrically trimmable electronic device, wherein a resistor of electrically modifiable material is formed by a first generally strip-shaped portion and by a second generally strip-shaped portion, which extend transversely with respect to one another and are in direct electrical contact in a crossing area. The first and second portions have respective ends connected to own contact regions, coupled to a current pulse source and are made of the same material or of the same composition of materials starting from a same resistive layer of the material having electrically modifiable resistivity, for example, a phase-change material, such as a Ge—Sb—Te alloy, or polycrystalline silicon, or a metal material used for thin-film resistors. The trimming is performed by supplying a trimming current to the second portion so as to heat the crossing area and modify the resistivity thereof, without flowing longitudinally in the first portion.

Abstract: An inverter includes: a PMOS comprising: a p-type source region, a p-type drain region, a p-channel region between the p-type source region and the p-type drain region, and a PMOS metal gate region; a NMOS, comprising: an n-type source region, an n-type drain region, an n-channel region between the n-type source region and the n-type drain region, and a NMOS metal gate region; an insulating layer above the p-channel region and the n-channel region, wherein the PMOS metal gate region and the NMOS metal gate region are above the insulating layer; and a gate contact between the NMOS metal gate region and the PMOS metal gate region.

Abstract: A method of forming a memory includes forming a first electrode and a second electrode within a first layer over a semiconductor substrate, forming a resistive-switching memory element and an antifuse element over the first layer, wherein the resistive-switching memory element includes a metal oxide layer and is electrically contacting the first electrode, wherein the metal oxide layer has a first thickness and a forming voltage that corresponds to the first thickness, wherein the antifuse element includes a dielectric layer and is electrically contacting the second electrode, and wherein the dielectric layer has a second thickness that is less than the first thickness and a dielectric breakdown voltage that is less than the forming voltage, and forming a third electrode and a fourth electrode within a second layer over the resistive-switching memory element and the antifuse element, wherein the third electrode is electrically contacting the resistive-switching memory element and the fourth electrode is elect

Abstract: A method comprises forming a gate trench between a plurality of gate spacers over a substrate, forming a resistor trench over the substrate, depositing a first layer on a bottom of the gate trench, a bottom of the resistor trench, sidewalls of the gate trench and sidewalls of the resistor trench, depositing a second layer over the first layer, depositing a gate electrode layer over the second layer and applying a chemical mechanical polish process to the gate electrode layer until the gate electrode layer is removed from the resistor trench.

Abstract: The silicon nitride layer 910 formed by plasma CVD using a gas containing a hydrogen compound such as silane (SiH4) and ammonia (NH3) is provided on and in direct contact with the oxide semiconductor layer 905 used for the resistor 354, and the silicon nitride layer 910 is provided over the oxide semiconductor layer 906 used for the thin film transistor 355 with the silicon oxide layer 909 serving as a barrier layer interposed therebetween. Therefore, a higher concentration of hydrogen is introduced into the oxide semiconductor layer 905 than into the oxide semiconductor layer 906. As a result, the resistance of the oxide semiconductor layer 905 used for the resistor 354 is made lower than that of the oxide semiconductor layer 906 used for the thin film transistor 355.

Abstract: A semiconductor memory device according to an embodiment has a memory cell array including: a plurality of lower wirings extending in the first direction; a plurality of upper wirings extending in the second direction, the upper wirings placed above the plurality of lower wirings; a plurality of memory cells provided at respective crossings of the plurality of lower wirings and the plurality of upper wirings; and an interlayer insulating film provided between the plurality of memory cells adjacent in the second direction, and the device is characterized in that the upper wiring includes: an upper firing first section deposited on the memory cell; and an upper wiring second section deposited on the interlayer insulating film, the upper wiring second section larger in crystal grain size than the upper wiring first section, and an upper surface of the memory cell is lower than an upper surface of the interlayer insulating film.

Abstract: The present invention provides a manufacturing technique of a semiconductor device and a display device using a peeling process, in which a transfer process can be conducted with a good state in which a shape and property of an element before peeling are kept. Further, the present invention provides a manufacturing technique of more highly reliable semiconductor devices and display devices with high yield without complicating the apparatus and the process for manufacturing. According to the present invention, an organic compound layer including a photocatalyst substance is formed over a first substrate having a light-transmitting property, an element layer is formed over the organic compound layer including a photocatalyst substance, the organic compound layer including a photocatalyst substance is irradiated with light which has passed through the first substrate, and the element layer is peeled from the first substrate.

Abstract: Semiconductor devices and structures, such as phase change memory devices, include peripheral conductive pads coupled to peripheral conductive contacts in a peripheral region. An array region may include memory cells coupled to conductive lines. Methods of forming such semiconductor devices and structures include removing memory cell material from a peripheral region and, thereafter, selectively removing portions of the memory cell material from the array region to define individual memory cells in the array region. Additional methods include planarizing the structure using peripheral conductive pads and/or spacer material over the peripheral conductive pads as a planarization stop material. Yet further methods include partially defining memory cells in the array region, thereafter forming peripheral conductive contacts, and thereafter fully defining the memory cells.

Abstract: A phase change memory cell includes a first electrode having a cylindrical portion. A dielectric material having a cylindrical portion is longitudinally over the cylindrical portion of the first electrode. Heater material is radially inward of and electrically coupled to the cylindrical portion of the first electrode. Phase change material is over the heater material and a second electrode is electrically coupled to the phase change material. Other embodiments are disclosed, including methods of forming memory cells which include first and second electrodes having phase change material and heater material in electrical series there-between.

Abstract: A method of fabricating a semiconductor device includes forming a first gate pattern and a dummy gate pattern on a first active area and a second active area of a substrate, respectively, the first gate pattern including a first gate insulating layer and a silicon gate electrode, removing the dummy gate pattern to expose a surface of the substrate in the second active area, forming a second gate pattern including a second gate insulating layer and a metal gate electrode on the exposed surface of the substrate, the first gate insulating layer having a thickness larger than a thickness of the second gate insulating layer, and forming a gate silicide on the silicon gate electrode after forming the second gate pattern.

Abstract: Embodiments of the present invention disclose a resistive memory and a method for fabricating the same. The resistive memory comprises a bottom electrode, a resistive layer and a top electrode. The resistive layer is located over the bottom electrode. The top electrode is located over the resistive layer. A conductive protrusion is provided on the bottom electrode. The conductive protrusion is embedded in the resistive layer, and has a top width smaller than a bottom width. Embodiments of the present invention further disclose a method for fabricating a resistive memory. According to the resistive memory and the method for fabricating the same provided by the embodiments of the present invention, by means of providing the conductive protrusion on the bottom electrode, a “lightning rod” effect may be occurred so that an electric field in the resistive layer is intensively distributed near the conductive protrusion.

Abstract: An integrated circuit device including a resistive random access memory (RRAM) cell formed over a substrate. The RRAM cell includes a top electrode having an upper surface. A blocking layer covers a portion of the upper surface. A via extends above the top electrode within a matrix of dielectric. The upper surface of the top electrode includes an area that interfaces with the blocking layer and an area that interfaces with the via. The area of the upper surface that interfaces with the via surrounds the area of the upper surface that interfaces with the blocking layer. The blocking layer is functional during processing to protect the RRAM cell from etch damage while being structured in such a way as to not interfere with contact between the overlying via and the top electrode.

Abstract: Resistive-switching memory elements having improved switching characteristics are described, including a memory element having a first electrode and a second electrode, a switching layer between the first electrode and the second electrode, the switching layer comprising a first metal oxide having a first bandgap greater than 4 electron volts (eV), the switching layer having a first thickness, and a coupling layer between the switching layer and the second electrode, the coupling layer comprising a second metal oxide having a second bandgap greater the first bandgap, the coupling layer having a second thickness that is less than 25 percent of the first thickness.

Abstract: The present disclosure provides a method of fabricating a resistive memory array. In one embodiment, a method of fabricating a resistive memory array includes forming a plurality of insulators and a conductive structure on a first substrate, performing a resistor-forming process to transform the insulators into a plurality of resistors, polishing the conductive structure to expose a plurality of contact points respectively electrically connected to the resistors, providing a second substrate having a plurality of transistors and a plurality of interconnect pads, bonding respectively the interconnect pads and the contact points, and removing the first substrate from the resistors and the conductive structure.

Abstract: A resistive-switching memory element is described. The memory element includes a first electrode, a porous layer over the first electrode including a point defect embedded in a plurality of pores of the porous layer, and a second electrode over the porous layer, wherein the nonvolatile memory element is configured to switch between a high resistive state and a low resistive state.

Abstract: A semiconductor device includes a semiconductor substrate, trench isolations, a sacrificial layer, a first resist protect oxide (RPO) layer, a second RPO layer and a silicide layer. The semiconductor substrate has first portions and second portions which are alternately disposed, and each of the second portions includes a first resist region with a first resistance, a second resist region with a second resistance and a silicide region. The second resistance is greater than the first resistance. The trench isolations are in the first portions. The sacrificial layer is on the first resist region. The first RPO layer is on the sacrificial layer. The first RPO layer together with the sacrificial layer have a first thickness. The second RPO layer is on the second resist region, in which the second RPO layer has a second thickness smaller than the first thickness. The silicide layer is on the silicide region.

Abstract: The present disclosure provides methods of making resistive random access memory (RRAM) cells. The RRAM cell includes a transistor and an RRAM structure. The RRAM structure includes a bottom electrode having a via portion and a top portion, a resistive material layer on the bottom electrode having a width that is same as a width of the top portion of the bottom electrode; a capping layer over the bottom electrode, a first spacer surrounding the capping layer and a top electrode, a second spacer surround the top portion of the bottom electrode and the first spacer, and the top electrode. The RRAM cell further includes a conductive material connecting the top electrode of the RRAM structure to a metal layer.

Abstract: According to one embodiment, an information recording device includes first and second electrodes, a variable resistance layer between the first and second electrodes, and a control circuit which controls the variable resistance layer to n (n is a natural number except 1) kinds of resistance. The variable resistance layer comprises a material filled between the first and second electrodes, and particles arranged in a first direction from the first electrode to the second electrode in the material, and each of the particles has a resistance lower than that of the material. A resistance of the variable resistance layer is decided by a short between the first electrode and at least one of the particles.

Abstract: According to one embodiment, a storage device includes first electrodes, second electrodes, a resistance change layer provided between the first electrodes and the second electrodes, and ion metal particles that are formed in an island form between the first electrodes and the resistance change layer and that contain a metal movable inside the resistance change layer. The first electrodes and the second electrodes are formed of a material which is more unlikely to be ionized as compared to the metal, and the first electrodes are in contact with the resistance change layer in an area around the ion metal particles.

Abstract: The present disclosure provides resistive random access memory (RRAM) structures and methods of making the same. The RRAM structures include a bottom electrode having protruded step portion that allows formation of a self-aligned conductive path with a top electrode during operation. The protruded step portion may have an inclination angle of about 30 degrees to 150 degrees. Multiple RRAM structures may be formed by etching through a RRAM stack.

Abstract: A resistive memory device capable of implementing a multi-level cell, a method of fabricating the same, and a memory apparatus and data processing system including the same are provided. The resistive memory device includes a lower electrode, a first phase-change material layer formed over the lower electrode, a second phase-change material layer formed to surround an outer sidewall of the first phase-change material layer, and an upper electrode formed over the first phase-change material layer and the second phase-change material layer.

Abstract: A method of fabricating a memory device is disclosed. In one aspect, the method comprises patterning a first conductive line extending in a first direction. The method additionally includes forming a free-standing pillar of a memory cell stack on the first conductive line after patterning the first conductive line. Forming the free-standing pillar includes depositing a memory cell stack comprising a selector material and a storage material over the conductive line and patterning the memory cell stack to form the free-standing pillar. The method further includes patterning a second conductive line on the pillar after patterning the memory cell stack, the second conductive line extending in a second direction crossing the first direction.

Abstract: Methods of selectively forming a metal-doped chalcogenide material comprise exposing a chalcogenide material to a transition metal solution, and incorporating transition metal of the transition solution into the chalcogenide material without substantially incorporating the transition metal into an adjacent material. The chalcogenide material is not silver selenide. Another method comprises forming a chalcogenide material adjacent to and in contact with an insulative material, exposing the chalcogenide material and the insulative material to a transition metal solution, and diffusing transition metal of the transition metal solution into the chalcogenide material while substantially no transition metal diffuses into the insulative material.

Abstract: Some embodiments include a method of forming a memory cell. A first portion of a switching region is formed over a first electrode. A second portion of the switching region is formed over the first portion using atomic layer deposition. The second portion is a different composition than the first portion. An ion source region is formed over the switching region. A second electrode is formed over the ion source region. Some embodiments include a memory cell having a switching region between a pair of electrodes. The switching region is configured to be reversibly transitioned between a low resistive state and a high resistive state. The switching region includes two or more discrete portions, with one of the portions not having a non-oxygen component in common with any composition directly against it in the high resistive state.

Abstract: A method of forming a variable resistive memory device includes forming a conductive pattern that alternates with a first insulation pattern along a first direction on a substrate that is parallel with a surface of the substrate, forming a preliminary sacrificial pattern on the conductive pattern that contacts a sidewall of the first insulation pattern, etching the conductive pattern using the preliminary sacrificial pattern as an etch masks to form a preliminary bottom electrode pattern, patterning the preliminary sacrificial pattern and the preliminary bottom electrode pattern to form a sacrificial pattern and a bottom electrode pattern that each include at least two portions which are separated from each other along a second direction intersecting the first direction, and replacing the sacrificial pattern with a variable resistive pattern.

Abstract: A method for fabricating a semiconductor device includes forming an impurity layer over a first conductive layer; forming a first metal oxide layer over the impurity layer, wherein the first metal oxide layer includes oxygen at a lower ratio than a stoichiometric ratio; diffusing an impurity from the impurity layer into the first metal oxide layer to form a first doped metal oxide layer; forming a second metal oxide layer over the first doped metal oxide layer; and forming a second conductive layer over the second metal oxide layer.

Abstract: The present invention relates to integrating a resistive memory device on top of an IC substrate monolithically using IC-foundry compatible processes.

Abstract: Providing for one time programmable, multi-level cell two-terminal memory is described herein. In some embodiments, the one time programmable, multi-level cell memory can have a 1 diode 1 resistor configuration, per memory cell. A memory cell according to one or more disclosed embodiments can be programmed to one of a set of multiple logical bits, and can be configured to mitigate or avoid erasure. Accordingly, the memory cell can be employed as a single program, non-erasable memory. Expressed differently, the memory cell can be referred to as a write once read many (WORM) category of memory.

Abstract: A flexible and/or transparent nonvolatile memory device can be fabricated on flexible substrates, together with ductile materials or transparent conductive oxide materials, and layers with thicknesses that allow flexibility and transparency. The ductile materials can include Ti, Ni, Nb, or Zr. The transparent conductive materials can include indium tin oxide, zinc oxide or aluminum doped zinc oxide. The nonvolatile memory devices can include resistive switching memory, phase change memory, magnetoresistive random access memory, or spin-transfer torque random access memory.

Abstract: Embodiments relate generally to semiconductors and memory technology, and more particularly, to systems, integrated circuits, and methods to implement a memory architecture that includes local bit lines for accessing subsets of memory elements, such as memory elements based on third dimensional memory technology. In at least some embodiments, an integrated circuit includes a cross-point memory array formed above a logic layer. The cross-point memory array includes X-lines and Y-lines, of which at least one Y-line includes groups of Y-line portions. Each of the Y-line portions can be arranged in parallel with other Y-line portions within a group of the Y-line portions. Also included are memory elements disposed between a subset of the X-lines and the group of the Y-line portions. In some embodiments, a decoder is configured to select a Y-line portion from the group of Y-line portions to access a subset of the memory elements.

Abstract: A semiconductor device includes a first electrode on a substrate, a selection device pattern, a variable resistance layer pattern, a first protective layer pattern, a second protective layer pattern and a second electrode. The selection device pattern is wider, in a given direction, than the variable resistance layer pattern. The first protective layer pattern is formed on a first pair of opposite sides of the variable resistance layer pattern. The second protective layer pattern is formed on a second pair of opposite of the variable resistance layer pattern. The second electrode is disposed on the variable resistance layer pattern.

Abstract: Provided is a three-dimensional resistance memory including a stack of layers. The stack of layers is encapsulated in a dielectric layer and is adjacent to at least one opening in the encapsulating dielectric layer. At least one L-shaped variable resistance spacer is disposed on at least a portion of the sidewall of the opening adjacent to the stack of layers. An electrode layer fills the remaining portion of the opening.

Abstract: A nano-ionic memory device is provided. The memory device includes a substrate, a chemically inactive lower electrode provided on the substrate, a solid electrolyte layer provided on the lower electrode and including a silver (Ag)-doped telluride (Te)-based nano-material, and an oxidizable upper electrode provided on the electrolyte layer.

Abstract: A method of producing a temperature sensing device is provided. The method includes forming at least one silicon layer and at least one electrode or contact to define a thermistor structure. At least the silicon layer is formed by printing, and at least one of the silicon layer and the electrode or contact is supported by a substrate during printing thereof. Preferably, the electrodes or contacts are formed by printing, using an ink comprising silicon particles having a size in the range 10 nanometers to 100 micrometers, and a liquid vehicle composed of a binder and a suitable solvent. In some embodiments the substrate is an object the temperature of which is to be measured. Instead, the substrate may be a template, may be sacrificial, or may be a flexible or rigid material. Various device geometries are disclosed.

Abstract: A method of fabricating a fin selector with a gated RRAM and the resulting device are disclosed. Embodiments include forming a bottom electrode layer and a hardmask on a semiconductor substrate; etching the hardmask, bottom electrode layer, and semiconductor substrate to form a fin-like structure; forming first and second dummy gate stacks on first and second side surfaces of the fin-like structure, respectively; forming spacers on vertical surfaces of the first and second dummy gate stacks; forming an ILD surrounding the spacers; removing the first and second dummy gate stacks, forming first and second cavities on first and second sides of the fin-like structure; forming an RRAM layer on the first and second side surfaces of the fin-like structure in the first and second cavities, respectively; and filling each of the first and second cavities with a top electrode.

Abstract: Nonvolatile memory elements that are based on resistive switching memory element layers are provided. A nonvolatile memory element may have a resistive switching metal oxide layer. The resistive switching metal oxide layer may have one or more layers of oxide. A resistive switching metal oxide may be doped with a dopant that increases its melting temperature and enhances its thermal stability. Layers may be formed to enhance the thermal stability of the nonvolatile memory element. An electrode for a nonvolatile memory element may contain a conductive layer and a buffer layer.

Abstract: Resistive-switching memory elements having improved switching characteristics are described, including a memory element having a first electrode and a second electrode, a switching layer between the first electrode and the second electrode, the switching layer comprising a first metal oxide having a first bandgap greater than 4 electron volts (eV), the switching layer having a first thickness, and a coupling layer between the switching layer and the second electrode, the coupling layer comprising a second metal oxide having a second bandgap greater the first bandgap, the coupling layer having a second thickness that is less than 25 percent of the first thickness.

Abstract: Some embodiments include a memory cell that has an electrode, a switching material over the electrode, a buffer region over the switching material, and an ion reservoir material over the buffer region. The buffer region includes one or more elements from Group 14 of the periodic table in combination with one or more chalcogen elements. Some embodiments include methods of forming memory cells.

Abstract: A semiconductor structure includes a substrate, a resist layer, a dielectric material, two U-shaped metal layers and two metals. The substrate has an isolation structure. The resist layer is located on the isolation structure. The dielectric material is located on the resist layer. Two U-shaped metal layers are located at the two sides of the dielectric material and on the resist layer. Two metals are respectively located on the two U-shaped metal layers. This way a semiconductor process for forming said semiconductor structure is provided.

Abstract: An array of vertically stacked tiers of memory cells includes a plurality of horizontally oriented access lines within individual tiers of memory cells and a plurality of horizontally oriented global sense lines elevationally outward of the tiers. A plurality of select transistors is elevationally inward of the tiers. A plurality of pairs of local first and second vertical lines extends through the tiers. The local first vertical line within individual of the pairs is in conductive connection with one of the global sense lines and in conductive connection with one of the two source/drain regions of one of the select transistors. The local second vertical line within individual of the pairs is in conductive connection with another of the two source/drain regions of the one select transistor. Individual of the memory cells include a crossing one of the local second vertical lines and one of the horizontal access lines and programmable material there-between.

Abstract: A phase-change memory cell having a reduced electrode-chalcogenide interface resistance and a method for making the phase-change memory cell are disclosed: An interface layer is formed between an electrode layer and a chalcogenide layer that and provides a reduced resistance between the chalcogenide-based phase-change memory layer and the electrode layer. Exemplary embodiments provide that the interface layer comprises a tungsten carbide, a molybdenum carbide, a tungsten boride, or a molybdenum boride, or a combination thereof. In one exemplary embodiment, the interface layer comprises a thickness of between about 1 nm and about 10 nm.

Abstract: A method of forming a circuitry includes providing a substrate comprising a plurality of die. Each die includes a plurality of resistive random access memory (RRAM) storage cells. The method further includes concurrently initializing substantially all of the RRAM storage cells on the same wafer. Initializing can include applying a voltage potential across the RRAM storage cells.

Abstract: A manufacturing method of a resistive random access storage unit, includes: forming a resistance layer on a first metal layer having a flat surface; forming a passivation layer on the resistance layer; performing an etching process to obtain a plurality of basic units, a basic unit comprising a first metal layer, a resistance layer, and a passivation layer, which are laminated sequentially; depositing a insulating dielectric layer, and flattening the insulating dielectric layer; etching the insulating dielectric layer and the passivation layer to form contacting holes corresponded to the basic units; filling metal wires in the contacting holes; forming a second metal layer. According to the above method, a uniformly distributed resistance can be formed on a whole wafer.

Abstract: A programmable logic circuit architecture using resistive memory elements. The proposed circuit architecture uses the conventional island-based Field Programmable Gate Array (FPGA) architecture, but with novel integration of CMOS-compatible resistive memory elements that can be programmed efficiently. In the proposed architecture, the programmable interconnects of FPGA are redesigned to use only resistive memory elements and metal wires. Then, the interconnects can be entirely fabricated over logic blocks to save area while keeping their architectural functions unchanged, and the programming transistors can be shared among resistive memory elements to save area. Finally, on-demand buffer insertion is proposed as the buffering solution to achieve more speedup.

Abstract: A resistive memory device and a fabrication method thereof are provided. The resistive memory device includes a bottom structure including a heating electrode, data storage materials, each of the data storage materials formed on the bottom structure in a confined structure perpendicular to the bottom structure, and having a lower diameter smaller than an upper diameter, an upper electrode formed on each of the data storage materials, and an insulation unit formed between adjacent data storage materials.

Abstract: A sequence of semiconductor processing steps permits formation of both vertical and horizontal nanometer-scale serpentine resistors and parallel plate capacitors within a common structure. The method of fabricating such a structure cleverly takes advantage of a CMP process non-uniformity in which the CMP polish rate of an insulating material varies according to a certain underlying topography. By establishing such topography underneath a layer of the insulating material, different film thicknesses of the insulator can be created in different areas by leveraging differential polish rates, thereby avoiding the use of a lithography mask. In one embodiment, a plurality of resistors and capacitors can be formed as a compact integrated structure within a common dielectric block, using a process that requires only two mask layers.

Abstract: A method of fabricating a semiconductor device is disclosed. The method includes providing a substrate including an isolation region, forming a resistor over the isolation region, and forming a contact over the resistor. The method also includes implanting with a dopant concentration that is step-increased at a depth of the resistor and that remains substantially constant as depth increases.

Abstract: According to one embodiment, a resistance change element includes: a first electrode; a second electrode; and a resistance change film provided between the first electrode and the second electrode, and the resistance change film including: a first transition metal oxide-containing layer; a second transition metal oxide-containing layer; and an intermediate layer provided between the first transition metal oxide-containing layer and the second transition metal oxide-containing layer, the intermediate layer having a higher crystallization temperature than the first transition metal oxide-containing layer and the second transition metal oxide-containing layer, and the intermediate layer including an amorphous material.

Abstract: Each of the step of forming a first variable resistance layer (18a) and the step of forming a second variable resistance layer (18b) includes performing a cycle once or plural times, the cycle consisting of a first step of introducing a source gas composed of molecules containing atoms of a transition metal; a second step of removing the source gas after the first step; a third step of introducing a reactive gas to form a transition metal oxide after the second step; and a fourth step of removing the reactive gas after the third step. The step of forming the first variable resistance layer (18a) is performed in a state in which the substrate is kept at a temperature at which a self-decomposition reaction of the source gas does not occur.

Abstract: A semiconductor structure includes a substrate and a resistor provided over the substrate. The resistor includes a first material layer, a second material layer, a first contact structure and a second contact structure. The first material layer includes at least one of a metal and a metal compound. The second material layer includes a semiconductor material. The second material layer is provided over the first material layer and includes a first sub-layer and a second sub-layer. The second sub-layer is provided over the first sub-layer. The first sub-layer and the second sub-layer are differently doped. Each of the first contact structure and the second contact structure provides an electrical connection to the second sub-layer of the second material layer.