An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

There is provided a monolithic three dimensional array of charge storage devices which includes a plurality of device levels, wherein at least one surface between two successive device levels is planarized by chemical mechanical polishing.

Dense arrays and charge storage devices

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.

Nonvolatile memory cell comprising a diode and a resistance-switching material

A memory array having memory cells comprising a diode and a phase change material is reliably programmed by maintaining all unselected memory cells in a reverse biased state. Thus leakage is low and assurance is high that no unselected memory cells are disturbed. In order to avoid disturbing unselected memory cells during sequential writing, previously selected word and bit lines are brought to their unselected voltages before new bit lines and word lines are selected. A modified current mirror structure controls state switching of the phase change material.

Structure and method for biasing phase change memory array for reliable writing

A memory cell according to the present invention comprises a bottom conductor, a doped semiconductor pillar, and a top conductor. The memory cell does not include a dielectric rupture antifuse separating the doped semiconductor pillar from either conductor, or within the semiconductor pillar. The memory cell is formed in a high-impedance state, in which little or no current flows between the conductors on application of a read voltage. Application of a programming voltage programs the cell, converting the memory cell from its initial high-impedance state to a low-impedance state. A monolithic three dimensional memory array of such cells can be formed, comprising multiple memory levels, the levels monolithically formed above one another.

Nonvolatile memory cell without a dielectric antifuse having high- and low-impedance states

A nonvolatile memory cell according to the present invention comprises a bottom conductor, a semiconductor pillar, and a top conductor. The semiconductor pillar comprises a junction diode, including a bottom heavily doped region, a middle intrinsic or lightly doped region, and a top heavily doped region, wherein the conductivity types of the top and bottom heavily doped region are opposite. The junction diode is vertically oriented and is of reduced height, between about 500 angstroms and about 3500 angstroms. A monolithic three dimensional memory array of such cells can be formed comprising multiple memory levels, the levels monolithically formed above one another.

Nonvolatile memory cell comprising a reduced height vertical diode

A method of making a semiconductor device includes forming a first photoresist layer over an underlying layer, patterning the first photoresist layer into a first photoresist pattern, wherein the first photoresist pattern comprises a plurality of spaced apart first photoresist features located over the underlying layer, and etching the underlying layer using the first photoresist pattern as a mask to form a plurality of first spaced apart features. The method further includes removing the first photoresist pattern, forming a second photoresist layer over the plurality of first spaced apart features, and patterning the second photoresist layer into a second photoresist pattern, wherein the second photoresist pattern comprises a plurality of second photoresist features covering edge portions of the plurality of first spaced apart features. The method also includes etching exposed portions of the plurality of first spaced apart features using the second photoresist pattern as a mask, such that a plurality of spaced apart edge portions of the plurality of first spaced apart features remain, and removing the second photoresist pattern.

Method for fabricating high density pillar structures by double patterning using positive photoresist

A method is provided for forming patterned features using a conductive hard mask, where the conductive hard mask protects those features during a subsequent trench etch to form Damascene conductors providing electrical connection to those features from above. The thickness of the hard mask provides a margin to avoid overetch during the trench etch which may be harmful to device performance. The method is advantageously used in formation of a monolithic three dimensional memory array.

Conductive hard mask to protect patterned features during trench etch

A non-volatile memory device contains a three dimensional stack of horizontal diodes located in a trench in an insulating material, a plurality of storage elements, a plurality of word lines extending substantially vertically, and a plurality of bit lines. Each of the plurality of bit lines has a first portion that extends up along at least one side of the trench and a second portion that extends substantially horizontally through the three dimensional stack of the horizontal diodes. Each of the horizontal diodes is a steering element of a respective non-volatile memory cell of the non-volatile memory device, and each of the plurality of storage elements is located adjacent to a respective steering element.

Three dimensional horizontal diode non-volatile memory array and method of making thereof

In formation of monolithic three dimensional memory arrays, a photomask may be used more than once. Reuse of a photomask creates second, third or more instances of reference marks used by the stepper to achieve alignment (alignment marks) and to measure alignment achieved (overlay marks) directly above prior instances of the same reference mark. The prior instances of the same reference mark may cause interference with the present instance of the reference mark, complicating alignment and measurement. Using the methods of the present invention, blocking structure is created vertically interposed between subsequent instances of the same reference mark, preventing interference.

Steven J. Radigan

Papers

Nonvolatile memory cell comprising a reduced height vertical diode

Method for fabricating high density pillar structures by double patterning using positive photoresist

Conductive hard mask to protect patterned features during trench etch

Three dimensional horizontal diode non-volatile memory array and method of making thereof

Masking of repeated overlay and alignment marks to allow reuse of photomasks in a vertical structure