SUNRISE MEMORY CORPORATION

A memory structure includes storage transistors organized as horizontal NOR memory strings where the storage transistors are thin-film ferroelectric field-effect transistors (FeFETs) having a ferroelectric gate dielectric layer formed adjacent an oxide semiconductor channel region. The ferroelectric storage transistors thus formed are junctionless transistors having no p/n junction in the channel. In some embodiments, the ferroelectric storage transistors in each NOR memory string share a common source line and a common bit line that are formed on a first side of the channel region, away from the ferroelectric gate dielectric layer, and in electrical contact with the oxide semiconductor channel region. The ferroelectric storage transistors in a NOR memory string are controlled by individual control gate electrodes that are formed adjacent the ferroelectric gate dielectric layer on a second side, opposite the first side, of the channel region.

A memory circuit includes an array of thin-film ferroelectric memory transistors arranged in multiple stacks of NOR memory strings in contact with local word line structures with global word lines arranged orthogonal to the array of NOR memory strings and aligned with a set of local word line structures provided across multiple stacks of NOR memory strings. The memory circuit includes a word line select transistor provided between each local word line structure and the associated global word line. The word line select transistor, when activated, selectively couples the gate terminal of a selected local word line structure to the associated global word line. Remaining local word line structures associated with the same global word line remain disconnected and therefore not selected. In this manner, parasitic capacitance on the global word line is reduced and unintended disturb to other unselected memory transistors is also reduced.

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.

In some embodiments, a memory device implements a tile-based architecture including an arrangement of independently and concurrently operable arrays or tiles of memory transistors where each tile includes memory transistors that are arranged in a three-dimensional array and a localized modular control circuit operating the memory transistors in the tile. The tile-based architecture of the memory device enables concurrent memory access to multiple tiles, which enables independent and concurrent memory operations to be carried out across multiple tiles. The tile-based concurrent access to the memory device has the benefits of increasing the memory bandwidth and lowering the tail latency of the memory device by ensuring high availability of storage transistors. In other embodiments, a memory module includes multiple semiconductor memory dies coupled to a memory controller where the semiconductor memory dies are partitioned into independently accessible memory channels with each memory channel being formed across the multiple semiconductor memory dies.

A memory structure including three-dimensional NOR memory strings and method of operation is disclosed. In some embodiments, the memory device implements partial polarization to provide a reference signal for read operation. The reference signal realizes a third logical state distinguishable from the first and second logical stages in the ferroelectric memory transistor, such as associated with the program and erase states. In another embodiment, the memory device provides a reference signal for read operation by averaging a first signal associated with a program state and a second signal associated with an erased state of the ferroelectric memory transistor. In some embodiments, the memory device implements one or more partial polarization states to provide a multi-level memory cell with more than one logical bit stored in each memory cell.

A memory structure includes storage transistors organized as horizontal NOR memory strings where the storage transistors are thin-film ferroelectric field-effect transistors (FeFETs) having a ferroelectric gate dielectric layer formed adjacent a semiconductor channel. In some embodiments, the semiconductor channel is formed by an oxide semiconductor material and the ferroelectric storage transistors are junctionless transistors with no p/n junction in the channel. In some embodiments, the ferroelectric storage transistors in each NOR memory string share a first conductive layer as a common source line and a second conductive layer as a common bit line, the first and second conductive layers being in electrical contact with the semiconductor channel. The ferroelectric storage transistors in a multiplicity of NOR memory strings are arranged to form semi-autonomous three-dimensional memory arrays (tiles) with each tile individually addressed and controlled by circuitry in the semiconductor substrate underneath each tile in cooperation with a memory controller.

A VNOR memory string includes: (a) first and second pillars embedded in multiple composite layers, each composite layer comprising an insulator layer and a conductor layer, the first and second pillars each comprising a first semiconductor material of a first conductivity; (b) a second semiconductor layer of a second conductivity type opposite the first conductivity type on the outside of third pillar also embedded in the composite layers, the third pillar contacting both the first and second pillars; and (c) a storage layer provided between the second semiconductor layer and each of the conductor layer in the composite layers.

By harnessing the ferroelectric phases in the charge storage material of thin-film storage transistors of a 3-dimensional array of NOR memory strings, the storage transistors are adapted to operate as ferroelectric field-effect transistors (“FeFETs”), thereby providing a very high-speed, high-density memory array.

A conductor-filled via formed in a staircase structure that is provided in conjunction with a 3-dimensional array of memory strings, where the staircase structure includes multiple steps with each step including a bit line layer and a source line layer. The conductor-filled via includes a conductor to electrically connect a top layer in a first step in the staircase structure to a buried contact provided under the staircase structure, the top layer being the bit line layer or the source line layer of the first step; and a spacer insulator lining the sidewalls of the conductor-filled via to isolate the conductor from at least a bottom layer of the first step and the bit line layer or the source line layer in any steps between the first step and the buried contact.

An integrated circuit includes a first semiconductor die having first memory circuits and a second semiconductor die having second memory circuits, the second memory circuits having a write latency shorter than that of the first memory circuits. The first semiconductor die and the second semiconductor die are interconnected by interconnections formed by wafer-level or chip-level bonding between the first and second semiconductor dies. The second semiconductor die includes an on-chip control circuit that controls operations of the first memory circuits and the second memory circuits to transfer data between the first memory circuits and the second memory circuits.