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US 12,322,447 B2Granted
Apparatus with multi-bit cell read mechanism and methods for operating the same
AssigneeMicron Technology, Inc.
InventorsMatteo Impala′, Mattia Robustelli, Innocenzo Tortorelli
Life of this patent
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Abstract
Methods, apparatuses and systems related to reading data from memory cells configured to store more than one bit are described. The apparatus may be configured to determine a polarity data associated with reading data stored at a target location. In reading the data stored at the target location, the apparatus may apply one or more voltage levels across different polarities according to the determined polarity data.
Claims17
A memory device, comprising:
- rewritable memory cells including multi-level cells (MLCs) that are each configured to store two bits using a set of storage states that correspond to a minimum threshold voltage (Vt), a maximum Vt, a ternary (T) state, and at least one intermediate (I) state for positive and negative polarities;
- and
- a logic circuit operably coupled to the memory cells and configured to:
- determine a polarity data associated with reading a target location amongst the MLCs;
- detect a storage state at the target location based on applying a sequence of voltage levels for a first polarity and then a second polarity,
- wherein the sequence of the first and second polarity is selected according to the polarity data and is configured to write over an intermediate Vt in distinguishing between the T state and the at least one I state,
- wherein the storage state is detected based on adjusting a voltage application sequence to (1) first apply one or more voltage levels matching the first polarity indicated by the polarity data for enabling detection of the intermediate Vt and then (2) one or more voltage levels for the second polarity that is opposite the first polarity, and
- wherein the determined polarity data indicates the first polarity representing that the target location is configured to implement the intermediate Vt using the first polarity;
- control application of a reprogramming voltage along the second polarity for reestablishing the storage state, wherein the reestablished storage state corresponds to the intermediate Vt,
- wherein, when the storage state of the target location corresponds to the intermediate Vt, the reprogramming voltage applied along the second polarity is configured to reestablish the intermediate Vt using the second polarity after the detection of the storage state instead of using the first polarity as was before the detection;
- and
- update the polarity data after detecting the storage state, wherein the polarity data is changed from the first polarity to the second polarity for a subsequent read operation at the target location.
9 more elements
An apparatus, comprising:
- rewritable memory cells including a subset of cells that are each configured to store more than one bit using a set of storage states that correspond to a minimum threshold voltage (Vt), a maximum Vt, a ternary (T) state, and at least one intermediate (I) state,
- wherein the subset of cells are multi-level cells (MLCs) that are each configured to store two bits,
- wherein the rewritable memory cells include a single-level cell (SLC) configured to store one bit that represents the polarity data for the target location;
- and
- a logic circuit operably coupled to the memory cells and configured to:
- determine a polarity data associated with reading a target location amongst the subset of cells, wherein the polarity data is updated by separately programming the SLC to represent the different value;
- detect a storage state at the target location based on applying a sequence of voltage levels for a first polarity and then a second polarity,
- wherein the sequence of the first and second polarity is selected according to the polarity data and
- wherein applying the sequence of voltage levels results in removing a previously established I state in distinguishing between the T state and the at least one I state;
- control application of a reprogramming voltage along the second polarity for reestablishing the storage state;
- and
- separate from or simultaneously with application of the reprogramming voltage, update the polarity data after detecting the storage state, wherein the polarity data is updated to a value different than before the detection of the storage state.
9 more elements
A method of operating a memory device that includes rewritable memory cells that are each configured to store more than one bit using a minimum threshold voltage (Vt), a maximum Vt, a ternary (T) state, and at least one intermediate (I) state, the method comprising:
- determining a polarity data associated with reading a target location amongst the subset of cells, wherein the determined polarity data represents a polarity setting for implementing an intermediate Vt at the target location;
- detecting a storage state at the target location based on applying a sequence of voltage levels for a first polarity and then a second polarity,
- wherein the sequence of the first and second polarity is selected according to the polarity data,
- wherein applying the sequence of voltage levels results in removing a previously established I state in distinguishing between the T state and the at least one I state,
- wherein detecting the storage state includes:
- first applying one or more voltage levels of the first polarity, wherein the first polarity matches the polarity setting to enable detection of the intermediate Vt;
- changing a polarity for read level voltages from the first polarity to the second polarity;
- and
- applying one or more voltage levels of the second polarity;
- controlling application of a reprogramming voltage along the second polarity for reestablishing the storage state,
- wherein, when the storage state of the target location corresponds to the intermediate Vt, controlling the application of the reprogramming voltage includes reestablishing the intermediate Vt at the target location using the second polarity;
- and
- separate from or simultaneously with application of the reprogramming voltage, updating the polarity data after detecting the storage state, wherein the polarity data is updated to a value different than before the detection of the storage state, wherein the polarity setting is updated from the first polarity to the second polarity after the detection of the storage state.
10 more elements
Dependencies are inferred from the claim text.