SUNRISE MEMORY CORPORATION

A semiconductor memory device implements a write disturb reduction method to reduce write disturb on unselected memory cells by alternating the order of the write logical “1” step and write logical “0” step in the write operations of selected memory cells associated with the same group of bit lines. In one embodiment, a method in an array of memory cells includes performing write operation on the memory cells in one of the memory pages to store write data into the memory cells where the write operation includes a first write step of writing a data of a first logical state and a second write step of writing data of a second logical state; and performing the write operation for each row of memory cells by alternately performing the first write step followed by the second write step and performing the second write step followed by the first write step.

A first circuit formed on a first semiconductor substrate is wafer-bonded to a second circuit formed on a second memory circuit, wherein the first circuit includes quasi-volatile or non-volatile memory circuits and wherein the second memory circuit includes fast memory circuits that have lower read latencies than the quasi-volatile or non-volatile memory circuits, as well as logic circuits. The volatile and non-volatile memory circuits may include static random-access memory (SRAM) circuits, dynamic random-access memory (DRAM) circuits, embedded DRAM (eDRAM) circuits, magnetic random-access memory (MRAM) circuits, embedded MRAM (eMRAM), or any suitable combination of these circuits.

An electronic device with embedded access to a high-bandwidth, high-capacity fast-access memory includes (a) a memory circuit fabricated on a first semiconductor die, wherein the memory circuit includes numerous modular memory units, each modular memory unit having (i) a three-dimensional array of storage transistors, and (ii) a group of conductors exposed to a surface of the first semiconductor die, the group of conductors being configured for communicating control, address and data signals associated the memory unit; and (b) a logic circuit fabricated on a second semiconductor die, wherein the logic circuit also includes conductors each exposed at a surface of the second semiconductor die, wherein the first and second semiconductor dies are wafer-bonded, such that the conductors exposed at the surface of the first semiconductor die are each electrically connected to a corresponding one of the conductors exposed to the surface of the second semiconductor die. The three-dimensional array of storage transistors may be formed by NOR memory strings.

A fabrication process for a memory structure including three-dimensional arrays of thin-film ferroelectric storage transistors is disclosed. In some embodiments, the ferroelectric storage transistors are organized in three-dimensional arrays of horizontal NOR memory strings. In some embodiments, the fabrication process uses a high aspect-ratio damascene process to form local word line structures that extends through the multiple layers of the three-dimensional memory structure. In particular, the high aspect-ratio local word line damascene process forms the gate stack layers, including the channel layer, the gate dielectric layer and the gate conductor layer, in the same sequence of additive deposition processes without any of the gate stack layers being subjected to any intervening etching process. In this manner, the integrity of the gate stack layers and their interfaces are well preserved and the transistor characteristics of the ferroelectric storage transistors are enhanced.

A method to ease the fabrication of high aspect ratio three dimensional memory structures for memory cells with feature sizes of 20 nm or less, or with a high number of memory layers. The present invention also provides an improved isolation between adjacent memory cells along the same or opposite sides of an active strip. The improved isolation is provided by introducing a strong dielectric barrier film between adjacent memory cells along the same side of an active strip, and by staggering memory cells of opposite sides of the active strip.

A memory circuit includes: (i) a semiconductor substrate having a planar surface, the semiconductor substrate having formed therein circuitry for memory operations; (ii) a memory array formed above the planar surface, the memory array having one or more electrodes to memory circuits in the memory array, the conductors each extending along a direction substantially parallel to the planar surface; and (iii) one or more transistors each formed above, alongside or below a corresponding one of the electrodes but above the planar surface of the semiconductor substrate, each transistor (a) having first and second drain/source region and a gate region each formed out of a semiconductor material, wherein the first drain/source region, the second drain/source region or the gate region has formed thereon a metal silicide layer; and (b) selectively connecting the corresponding electrode to the circuitry for memory operations.

A staggered memory cell architecture staggers memory cells on opposite sides of a shared bit line preserves memory cell density, while increasing the distance between such memory cells, thereby reducing the possibility of a disturb. In one implementation, the memory cells along a first side of a shared bit line are connected to a set of global word lines provided underneath the memory structure, while the memory cells on the other side of the shared bit line—which are staggered relative to the memory cells on the first side—are connected to global word lines above the memory structure.

A fabrication process for a memory structure including three-dimensional arrays of thin-film ferroelectric storage transistors is disclosed. In some embodiments, the ferroelectric storage transistors are organized in three-dimensional arrays of horizontal NOR memory strings. In some embodiments, the fabrication process uses a liner underlayer in the deposition process of the channel layer where the liner underlayer provides a uniform surface for the deposition of the channel layer and also serves as an etch stop layer in the subsequent metal replacement process. In another embodiment, the fabrication process applies a liner layer in vertical shafts during the local word line process to reduce or eliminate irregular features in the local word line structures, thereby enhancing the electrical characteristics and reliability of the memory arrays thus formed.

A method for forming 3-dimensional vertical NOR-type memory string arrays uses damascene local bit lines is provided. The method of the present invention also avoids ribboning by etching local word lines in two steps. By etching the local word lines in two steps, the aspect ratio in the patterning and etching of stack of local word lines (“word line stacks”) is reduced, which improves the structural stability of the word line stacks.

A thin-film storage transistor formed in a memory array above a planar surface of a semiconductor substrate, includes (a) first and second planar dielectric layers, each being substantially parallel the planar surface of the semiconductor substrate; (b) a first semiconductor layer of a first conductivity having an opening therein; (c) second and third semiconductor layers of a second conductivity type opposite the first conductivity type, located on two opposite sides of the first semiconductor layer; (d) a charge-storage layer provided in the opening adjacent and in contact with the first semiconductor layer; and (e) a first conductor provided in the opening separated from the first semiconductor layer by the charge storage layer, wherein the first, second and third semiconductor layers are each provided as a planar layer of materials between the first and second dielectric layers. In this configuration, the first, second and third semiconductor layers and the first conductor provide a channel region, a drain region, a source region and a gate electrode of the thin-film storage transistor.