Seagate Technology Incorporated

Seagate Technologies, Inc.

Seagate Technolagy LLC

Darshana H Mehta

Jon David Trantham

Antoine Khoueir

Praveen Viraraghavan

Mohamad H El-Batal

John West Dykes

Ian James Gilbert

Matthew J Totin

Sangita Shreedharan Kalarickal

Kurt W Getreuer

Mehmet Emin Aklik

Nicholas Odin Lien

Christopher Joseph Curl

Ara Patapoutian

Colin Hill

Method and apparatus for managing a front-end cache formed of ferroelectric memory element (FME) cells. Prior to storage of writeback data associated with a pending write command from a client device, an intelligent cache manager circuit forwards a first status value indicative that sufficient capacity is available in the front-end cache for the writeback data. Non-requested speculative readback data previously transferred to the front-end cache from the main NVM memory store may be jettisoned to accommodate the writeback data. A second status value may be supplied to the client device if insufficient capacity is available to store the writeback data in the front-end cache, and a different, non-FME based cache may be used in such case. Mode select inputs can be supplied by the client device specify a particular quality of service level for the front-end cache, enabling selection of suitable writeback and speculative readback data processing strategies.

Intelligent management of ferroelectric memory in a data storage device

Apparatus and method for managing data in a non-volatile memory (NVM) having an array of ferroelectric memory cells (FMEs). A data set received from an external client device is programmed to a group of the FMEs at a target location in the NVM using a selected profile. The selected profile provides different program characteristics, such as applied voltage magnitude and pulse duration, to achieve desired levels of power used during the program operation, endurance of the data set, and latency effects associated with a subsequent read operation to retrieve the data set. The profile may be selected from among a plurality of profiles for different operational conditions. The ferroelectric NVM may form a portion of a solid-state drive (SSD) storage device. Different types of FMEs may be utilized including ferroelectric tunneling junctions (FTJs), ferroelectric random access memory (FeRAM), and ferroelectric field effect transistors (FeFETs).

Balancing power, endurance and latency in a ferroelectric memory

A system on chip (SOC) integrated circuit device having an incorporated ferroelectric memory configured to be selectively refreshed, or not, depending on different operational modes. The ferroelectric memory is formed of an array of ferroelectric memory elements (FMEs) characterized as non-volatile, read-destructive semiconductor memory cells each having at least one ferroelectric layer. The FMEs can include FeRAM, FeFET or FTJ constructions. A read/write circuit writes data to the FMEs and subsequently reads back data from the FMEs responsive to respective write and read signals supplied by a processor circuit of the SOC. A refresh circuit is selectively enabled in a first normal mode to refresh the FMEs after a read operation, and is selectively disabled in a second exception mode so that the FMEs are not refreshed after a read operation. The FMEs can be used as a main memory, a cache, a buffer, an OTP, a keystore, etc.

System on chip (SOC) with processor and integrated ferroelectric memory

A data storage system can utilize one or more data storage devices that employ a solid-state non-volatile read destructive memory consisting of ferroelectric memory cells. A leveling strategy can be generated by a wear module connected to the memory with the leveling strategy prescribing a plurality of memory cell operating parameters associated with different amounts of cell wear. The wear module may monitor activity of a memory cell and detect an amount of wear in the memory cell as a result of the monitored activity, which can prompt changing a default set of operating parameters for the memory cell to a first stage of operating parameters, as prescribed by the leveling strategy, in response to the detected amount of wear.

Read destructive memory wear leveling system

A non-volatile memory (NVM) is formed of memory cells each having multiple ferroelectric memory elements (FMEs). Each FME stores data in relation to an electrical polarity of a recording layer formed of ferroelectric or anti-ferroelectric material. Each multi-FME memory cell is coupled to a set of external control lines activated by a control circuit in a selected order to perform program and/or read operations upon the FMEs. The FMEs may share a nominally identical construction or may have different constructions. Data are programmed and written responsive to the respective program/read responses of the FMEs. Constructions can include ferroelectric tunneling junctions (FTJs), ferroelectric random access memory (FeRAM), and ferroelectric field effect transistors (FeFETs). The NVM may form a portion of a data storage device, such as a solid-state drive (SSD).

Non-volatile memory cell with multiple ferroelectric memory elements (FMEs)

Apparatus and method for managing data in a processing system, such as but not limited to a data storage device such as a solid-state drive (SSD). A ferroelectric stack register memory has a first arrangement of ferroelectric memory cells (FMEs) of a first construction and a second arrangement of FMEs of a different, second construction arranged to provide respective cache lines for use by a controller, such as a programmable processor. A pointer mechanism is configured to provide pointers to point to each of the respective cache lines based on a time sequence of operation of the processor. Data sets can be migrated to the different arrangements by the controller as required based on the different operational characteristics of the respective FME constructions. The FMEs may be non-volatile and read-destructive. Refresh circuitry can be selectively enacted under different operational modes.

Stack register having different ferroelectric memory element constructions

A memory device formed of ferroelectric field effect transistors (FeFETs). The memory device can be used as a front end buffer, such as in a data storage device having a non-volatile memory (NVM). A controller can be configured to transfer user data between the NVM and an external client (host) via the buffer. The FeFETs can be arranged in a two-dimensional (2D) or a three-dimensional (3D) array. A monitor circuit can be used to monitor operation of the FeFETs. An optimization controller can be used to adjust at least one operational parameter associated with the FeFETs responsive to the monitored operation by the monitor circuit. The FeFETs may require a refresh operation after each read operation. A power down sequence can involve a read operation without a subsequent refresh operation to wipe the FeFETs, the read operation jettisoning the data read from the buffer memory.

Front end buffer having ferroelectric field effect transistor (FeFET) based memory

A data storage system can employ a read destructive memory configured to fill a first cache with a first data set from a data repository prior to populating a second cache with a second data set describing the first data set with the first and second cache each having non-volatile ferroelectric memory cells. An entirety of the first cache may be read in response to a cache hit in the second cache with the cache hit responsive to a data read command from a host and with the first cache being read without a refresh operation restoring the data of the first cache.

Intelligent cache with read destructive memory cells

A data storage system can employ a read destructive memory configured with multiple levels. A non-volatile memory unit can be programmed with a first logical state in response to a first write voltage of a first hysteresis loop by a write controller prior to being programmed to a second logical state in response to a second write voltage of the first hysteresis loop, as directed by the write controller. The first and second logical states may be present concurrently in the non-volatile memory unit and subsequently read concurrently as the first logical state and the second logical state.

Data storage with multi-level read destructive memory

Weak erase detection and mitigation techniques are provided that detect permanent failures in solid-state storage devices. One exemplary method comprises obtaining an erase fail bits metric for a solid-state storage device; and detecting a permanent failure in at least a portion of the solid-state storage device causing weak erase failure mode by comparing the erase fail bit metric to a predefined fail bits threshold. In at least one embodiment, the method also comprises mitigating for the permanent failure causing the weak erase failure mode for one or more cells of the solid-state storage device. The mitigating for the permanent failure comprises, for example, changing a status of the one or more cells to a defective state and/or a retired state. The detection of the permanent failure causing the weak erase failure mode comprises, for example, detecting the weak erase failure mode without an erase failure.

Detection and mitigation for solid-state storage device read failures due to weak erase

Technologies are described herein for or extending the lifespan of a solid-state drive by using worn-out MLC flash blocks in SLC mode to extend their useful life. Upon identifying a first storage location in the storage media of an SSD as a candidate for defecting, the first storage location is switched from a first programming mode to a second programming mode, where the second programming mode results in a lower storage density of storage locations than the first programming mode. In conjunction with switching the first storage location to the first programming mode, a second storage location in the storage media is switched from the second programming mode to the first programming mode to ensure that the total capacity of the storage media remains at or above the rated capacity.

Extending the life of a solid state drive by using MLC flash blocks in SLC mode

Read error mitigation in solid-state memory devices. A solid-state drive (SSD) includes a read error mitigation module that monitors one or more memory regions. In response to detecting uncorrectable read errors, memory regions of the memory device may be identified and preemptively retired. Example approaches include identifying a memory region as being suspect such that upon repeated read failures within the memory region, the memory region is retired. Moreover, memory regions may be compared to peer memory regions to determine when to retire a memory region. The read error mitigation module may trigger a test procedure on a memory region to detect the susceptibility of a memory region to read error failures. By detecting read error failures and retirement of a memory regions, data loss and/or data recovery processes may be limited to improve drive performance and reliability.

Mitigation of solid state memory read failures with a testing procedure

Read error mitigation in solid-state memory devices. A solid-state drive (SSD) includes a read error mitigation module that monitors one or more memory regions. In response to detecting uncorrectable read errors, memory regions of the memory device may be identified and preemptively retired. Example approaches include identifying a memory region as being suspect such that upon repeated read failures within the memory region, the memory region is retired. Moreover, memory regions may be compared to peer memory regions to determine when to retire a memory region. The read error mitigation module may trigger a test procedure on a memory region to detect the susceptibility of a memory region to read error failures. By detecting read error failures and retirement of a memory region, data loss and/or data recovery processes may be limited to improve drive performance and reliability.

Mitigation of solid state memory read failures

Method and apparatus for managing data in a non-volatile memory (NVM) of a storage device, such as a solid-state drive (SSD). In some embodiments, flash memory cells are arranged along word lines to which read voltages are applied to sense programmed states of the memory cells, with the flash memory cells along each word line being configured to concurrently store multiple pages of data. An encoder circuit is configured to apply error correction encoding to input data to form code words having user data bits and code bits, where an integral number of the code words are written to each page. A reference voltage calibration circuit is configured to randomly select a single selected code word from each page and to use the code bits from the single selected code word to generate a set of calibrated read voltages for the associated page.

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Shakopee, MN, United States of America

Darshana H Mehta