Abstract:
Measuring current-voltage (I-V) characteristics of a solar cell using a lamp that emits light, a substrate that includes a plurality of solar cells, a positive electrode attached to the solar cells, and a negative electrode peripherally deposited around each of the solar cells and connected to a common ground, an articulation platform coupled to the substrate, a multi-probe switching matrix or a Z-stage device, a programmable switch box coupled to the multi-probe switching matrix or Z-stage device and selectively articulating the probes by raising the probes until in contact with at least one of the positive electrode and the negative electrode and lowering the probes until contact is lost with at least one of the positive electrode and the negative electrode, a source meter coupled to the programmable switch box and measuring the I-V characteristics of the substrate.
Abstract:
Provided are memory cells including resistive switching layers having silicon, oxygen, and nitrogen as well as embedded resistor layers having a metal, silicon, and nitrogen. In some embodiments, silicon may be partially or completely replaced with aluminum. The embedded resistor may also have oxygen. A resistive switching layer directly interfaces an embedded resistor layer of the same cell. A portion of each layer forming this interface may be formed substantially of silicon nitride and may be formed in the same deposition chamber without breaking vacuum. For example, these portions may be formed by sequential atomic layer deposition cycles. However, silicon concentrations in these portions may be different. Specifically, the silicon concentration of the embedded resistor portion may be less than the silicon concentration of the resistive switching layer portion. This variation may be achieved by varying one or more process conditions during fabrication of the memory cell.
Abstract:
Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies. Therefore, the metal oxide film stacks have improved switching performance and reliability during memory cell applications compared to traditional hafnium oxide based stacks of previous memory cells.
Abstract:
Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 Å and about 100 Å, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.
Abstract:
Provided are voltage controlling assemblies that may be operable as clocks and/or oscillators. A voltage controlling assembly may include a comparator and a variable resistance device connected to one differential signal node of the comparator. The other node may be connected to a capacitor. Alternatively, no capacitors may be used in the assembly. During operation of the voltage controlling assembly, the variable resistance device changes its resistance between two different resistive states. The change from a low to a high resistive state may be associated with a voltage spike at the differential signal node of the comparator and trigger a response from the comparator. This resistance change may have a delay determining an operating frequency of the voltage controlling assembly. Specifically, the variable resistance device in the low resistive state may be kept for a period of time at a certain voltage before it switches into the high resistive state.
Abstract:
Provided are resistive random access memory (ReRAM) cells having diffusion barrier layers formed from various materials, such as beryllium oxide or titanium silicon nitrides. Resistive switching layers used in ReRAM cells often need to have at least one inert interface such that substantially no materials pass through this interface. The other (reactive) interface may be used to introduce and remove defects from the resistive switching layers causing the switching. While some electrode materials, such as platinum and doped polysilicon, may form inert interfaces, these materials are often difficult to integrate. To expand electrode material options, a diffusion barrier layer is disposed between an electrode and a resistive switching layer and forms the inert interface with the resistive switching layer. In some embodiments, tantalum nitride and titanium nitride may be used for electrodes separated by such diffusion barrier layers.
Abstract:
Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. The ReRAM cells may include a first layer formed on a substrate. The first layer may be operable as a bottom electrode. The ReRAM cells may also include a second layer formed over the first layer. The second layer may be operable as a variable resistance layer configured to switch reversibly between at least a first resistive state and a second resistive state. The ReRAM cells may further include a third layer formed over the second layer. The third layer may have an electrical resistivity that is substantially constant. Moreover, the third layer may include a ternary metal carbide. The ReRAM cells may also include a fourth layer formed over the third layer. The fourth layer may be operable as a top electrode.
Abstract:
Designs and programming schemes can be used to form memory arrays having low power, high density and good data retention. High resistance interconnect lines can be used to partition the memory array can be partitioned into areas of high data retention and areas of low data retention. Variable gate voltages can be used in control transistors to store memory values having different data retention characteristics.
Abstract:
A nonvolatile memory device contains a resistive switching memory element with improved device switching performance and life and methods for forming the same. The nonvolatile memory device has a first layer on a substrate, a resistive switching layer on the first layer, and a second layer. The resistive switching layer is disposed between the first layer and the second layer and the resistive switching layer comprises a material having the same morphology as the top surface of the first layer. A method of forming a nonvolatile memory element in a ReRAM device includes forming a resistive switching layer on a first layer and forming a second layer, so that the resistive switching layer is disposed between the first layer and the second layer. The resistive switching layer comprises a material formed with the same morphology as the top surface of the first layer.
Abstract:
Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof using metal organic chemical vapor deposition (MOCVD). Specifically, the MOCVD is used to form a resistive switching layer including oxides of at least two elements. The resistive switching layer may have a variable composition throughout its thickness, which may be achieved by dynamically varying flow rates of metal organic precursors during MOCVD of the resistive switching layer. In some embodiments, the first element may be a transition metal, while the second element may be a component forming an insulating oxide. The second element may be concentrated in the middle of the resistive switching layer between its bottom and top sides and may not be present at either one of these sides. Such distribution of materials allows controlling the size and composition of a switching zone within the resistive switching layer and reducing power needed for switching.