Abstract: A method is described for forming a semiconductor device comprising a bipolar transistor having a base region, an emitter region and a collector region, wherein the base region comprises polycrystalline semiconductor material formed by crystallizing silicon, germanium or silicon germanium in contact with a silicide, germanide or silicide germanide. The emitter region and collector region also may be formed from polycrystalline semiconductor material formed by crystallizing silicon, germanium or silicon germanium in contact with a silicide, germanide or silicide germanide forming metal. The polycrystalline semiconductor material is preferably silicided polysilicon, which is formed in contact with C49phase titanium silicide.

Abstract: Ions are implanted into a silicon donor body, defining a cleave plane. A first surface of the donor body is affixed to a receiver element, and a lamina is exfoliated at the cleave plane, creating a second surface of the lamina. There is damaged silicon at the second surface, which will compromise the efficiency of a photovoltaic cell formed from the lamina. A selective etchant, having an etch rate which is positively correlated with the concentration of structural defects in silicon, is used to remove the damaged silicon at the second surface, while removing very little of the relatively undamaged lamina.

Abstract: In a novel nonvolatile memory cell formed above a substrate, a diode is paired with a reversible resistance-switching material, preferably a metal oxide or nitride such as, for example, NixOy, NbxOy, TixOy, HfxOy, AlxOy, MgxOy, CoxOy, CrxOy, VxOy, ZnxOy, ZrxOy, BxNy, and AlxNy. In preferred embodiments, the diode is formed as a vertical pillar disposed between conductors. Multiple memory levels can be stacked to form a monolithic three dimensional memory array. In some embodiments, the diode comprises germanium or a germanium alloy, which can be deposited and crystallized at relatively low temperatures, allowing use of aluminum or copper in the conductors. The memory cell of the present invention can be used as a rewriteable memory cell or a one-time-programmable memory cell, and can store two or more data states.

Abstract: A very thin photovoltaic cell is formed by implanting gas ions below the surface of a donor body such as a semiconductor wafer. Ion implantation defines a cleave plane, and a subsequent step exfoliates a thin lamina from the wafer at the cleave plane. A photovoltaic cell, or all or a portion of the base or emitter of a photovoltaic cell, is formed within the lamina. In preferred embodiments, the wafer is affixed to a receiver before the cleaving step. Electrical contact can be formed to both surfaces of the lamina, or to one surface only.

Abstract: A bottom-gate thin film transistor having a silicide gate is described. This transistor is advantageously formed as SONOS-type nonvolatile memory cell, and methods are described to efficiently and robustly form a monolithic three dimensional memory array of such cells. The fabrication methods described avoid photolithography over topography and difficult stack etches of prior art monolithic three dimensional memory arrays of charge storage devices. The use of a silicide gate rather than a polysilicon gate allows increased capacitance across the gate oxide.

Abstract: A memory array is provided that includes a first memory level, a second memory level and a conductor shared between the first and second memory levels. The first memory level includes a first diode and a first resistivity-switching material layer coupled in series with the first diode. The second memory level includes a second diode and a second resistivity-switching material layer coupled in series with the second diode. The first and second resistivity-switching material layers each comprise one or more of NiXOy, NbxOy, TixOy, HfxOy, AlxOy, MgxOy, CoxOy, CrxOy, VxOy, ZnxOy, ZrxOy, BxNy, and AlxNy. Numerous other aspects are provided.

Abstract: Oxides of both nickel and cobalt have lower resistivity than either nickel oxide or cobalt oxide. Nickel oxide and cobalt oxide can be reversibly switched between two or more stable resistivity states by application of suitable electrical pulses. It is expected that oxides including both nickel and cobalt, or (NixCoy)O, will switch between resistivity states at lower voltage and/or current than will nickel oxide or cobalt oxide. A layer of (NixCoy)O can be paired with a diode or transistor to form a nonvolatile memory cell.

Abstract: In embodiments of the invention, a method of forming a monolithic three-dimensional memory array is provided, the method including forming a first memory level that includes a plurality of memory cells, each memory cell comprising a plurality of conductors comprising aluminum or copper, and forming a silicon diode in each memory cell, wherein the silicon diode is formed at temperatures compatible with the conductors. The silicon diode may be formed using a hot wire chemical vapor deposition technique, for example. Other aspects are also described.

Abstract: A nonvolatile memory device includes at least one memory cell which comprises a diode and a metal oxide antifuse dielectric layer, and a first electrode and a second electrode electrically contacting the at least one memory cell. In use, the diode acts as a read/write element of the memory cell by switching from a first resistivity state to a second resistivity state different from the first resistivity state in response to an applied bias.

Abstract: A first memory level includes a first plurality of memory cells that includes every memory cell in the first memory level. Each memory cell includes a vertically oriented p-i-n diode in the form of a pillar that includes a bottom heavily doped p-type region, a middle intrinsic or lightly doped region, and a top heavily doped n-type region. The first plurality of memory cells includes programmed cells and unprogrammed cells, wherein programmed cells comprise at least half of the first plurality of memory cells. Current flowing through the p-i-n diodes of at least 99 percent of the programmed cells when a voltage between about 1.5 volts and about 3.0 volts is applied between the bottom heavily doped p-type region and the top heavily doped n-type region is at least 1.5 microamps.

Abstract: A layer of resistivity-switching metal oxide or nitride can attain at least two stable resistivity states. Such a layer may be used in a state-change element in a nonvolatile memory cell, storing its data state, for example a “0” or a “1”, in this resistivity state. Including additional metal atoms in a layer of such a resistivity-switching metal oxide or nitride compound decreases the current required to cause switching between resistivity states, reducing power requirements for an array of memory cells storing data in the resistivity state of such a layer. In various embodiments a memory cell may include a layer of resistivity-switching metal oxide or nitride compound with added metal formed in series with another element, such as a diode or a transistor.

Abstract: A method is described for isotropic or nearly isotropic shallow doping of a non-planar surface exposed in a void. The results of ion implantation, a common doping method, are inherently planar. Some fabrication methods and devices may require doping a surface of a non-planar feature exposed in a void, such as a trench. The feature is doped by flowing a gas which will provide the dopant over the exposed surfaces, or by exposing the surfaces to a plasma including the dopant. The feature may be a patterned feature, including a top surface and a sidewall. In a preferred embodiment, a semiconductor feature having a top surface and a sidewall is exposed in a trench formed in a dielectric, and a gas providing a p-type or n-type dopant is flowed in the trench, providing a p-type or n-type dopant to the semiconductor.

Abstract: In a novel nonvolatile memory cell formed above a substrate, a diode is paired with a reversible resistance-switching material, preferably a metal oxide or nitride such as, for example, NixOy, NbxOy, TixOy, HFxOy, AlxOy, MgxOy, CoxOy, CrxOy, VxOy, ZnxOy, ZrxOy, BxNy, and AlxNy. In preferred embodiments, the diode is formed as a vertical pillar disposed between conductors. Multiple memory levels can be stacked to form a monolithic three dimensional memory array. In some embodiments, the diode comprises germanium or a germanium alloy, which can be deposited and crystallized at relatively low temperatures, allowing use of aluminum or copper in the conductors. The memory cell of the present invention can be used as a rewriteable memory cell or a one-time-programmable memory cell, and can store two or more data states.

Abstract: A nonvolatile memory cell includes a layer of a resistivity-switching metal oxide or nitride compound, the metal oxide or nitride compound including one metal, and a dielectric rupture antifuse formed in series. The dielectric rupture antifuse may be either in its initial, non-conductive state or a ruptured, conductive state. The resistivity-switching metal oxide or nitride layer can be in a higher- or lower-resistivity state. By using both the state of the resistivity-switching layer and the antifuse to store data, more than two bits can be stored per memory cell.

Abstract: A nonvolatile memory cell comprising a diode formed of semiconductor material can store memory states by changing the resistance of the semiconductor material by application of a set pulse (decreasing resistance) or a reset pulse (increasing resistance.) In preferred embodiments, set pulses are applied with the diode under forward bias, while reset pulses are applied with the diode in reverse bias. By switching resistivity of the semiconductor material of the diode, a memory cell can be either one-time programmable or rewriteable, and can achieve two, three, four, or more distinct data states.

Abstract: A method of operating a nonvolatile memory cell includes providing the nonvolatile memory cell comprising a diode which is fabricated in a first resistivity, unprogrammed state, and applying a forward bias to the diode having a magnitude greater than a minimum voltage required for programming the diode to switch the diode to a second resistivity, programmed state. The second resistivity state is lower than the first resistivity state.

Abstract: A nonvolatile memory cell comprising doped semiconductor material and a diode can store memory states by changing the resistance of the doped semiconductor material by application of a set pulse (decreasing resistance) or a reset pulse (increasing resistance.) Set pulses are of short duration and above a threshold voltage, while reset pulses are longer duration and below a threshold voltage. In some embodiments multiple resistance states can be achieved, allowing for a multi-state cell, while restoring a prior high-resistance state allows for an rewriteable cell. In some embodiments, the diode and a switchable memory formed of doped semiconductor material are formed in series, while in other embodiments, the diode itself serves as the semiconductor switchable memory element.

Abstract: A method is described for forming a thin film transistor having its current-switching region in polycrystalline semiconductor material which has been crystallized in contact with titanium silicide, titanium silicide-germanide, or titanium germanide. The titanium silicide, titanium silicide-germanide, or titanium germanide is formed having feature size no more than 0.25 micron in the smallest dimension. The small feature size tends to inhibit the phase transformation from C49 to C54 phase titanium silicide. The C49 phase of titanium silicide has a very close lattice match to silicon, and thus provides a crystallization template for the silicon as it forms, allowing formation of large-grain, low-defect silicon. Titanium does not tend to migrate through the silicon during crystallization, limiting the danger of metal contamination. In preferred embodiments, the transistors thus formed may be, for example, field-effect transistors or bipolar junction transistors.

Abstract: A method is disclosed to form an upward-pointing p-i-n diode formed of deposited silicon, germanium, or silicon-germanium. The diode has a bottom heavily doped p-type region, a middle intrinsic or lightly doped region, and a top heavily doped n-type region. The top heavily doped p-type region is doped with arsenic, and the semiconductor material of the diode is crystallized in contact with an appropriate silicide, germanide, or silicide-germanide. A large array of such upward-pointing diodes can be formed with excellent uniformity of current across the array when a voltage above the turn-on voltage of the diodes is applied. This diode is advantageously used in a monolithic three dimensional memory array.

Abstract: A nonvolatile memory cell includes: a rail-shaped first conductor formed at a first height above a substrate; a rail-shaped second conductor formed above the first conductor; and a vertically oriented first pillar comprising a p-i-n first diode; wherein the first pillar is disposed between the second conductor and the first conductor; wherein the first diode comprises an intrinsic or lightly doped region; and wherein the intrinsic or lightly doped region has a first thickness of about 300 angstroms or greater. Numerous additional aspects are provided.