A semiconductor memory apparatus includes an address generation circuit and an operation determination circuit. The address generation circuit generates a refresh target address that corresponds to a word line, among a plurality of word lines, the word line being adjacent to another word line in which row hammering has occurred. The operation determination circuit configured to generate an address matching information by comparing a row hammering address with the refresh target address.

A memory device includes a memory cell array, a random bit generator, a comparator and a refresh controller. The memory cell array includes a plurality of memory cells coupled to a plurality of word-lines. The random bit generator generates a random binary code having a predetermined number of bits. The comparator compares the random binary code and a reference binary code to output a matching signal based on a result of the comparison. The refresh controller refreshes target memory cells from among the plurality of memory cells based on addresses accessed by a memory controller during a sampling period randomly determined based on the matching signal and a refresh command from the memory controller.

A method includes determining a first memory access count threshold for a first word line of a block of memory cells and determining a second memory access count threshold for a second word line of the block of memory cells. The second memory access count threshold can be greater than the first memory access count threshold. The method can further include incrementing a memory block access count corresponding to the block of memory cells that includes the first word line and the second word line in response to receiving a memory access command and refreshing the first word line when the memory block access count corresponding to the block of memory cells is equal to the first memory access count threshold.

A semiconductor memory device includes a mammy cell array including a plurality of memory cells and a control logic circuit configured to control the semiconductor memory device, The control logic circuit includes a mode register and a remaining lifetime calculating device configured to count usage metrics based on one or more of the following: a number of clock signals received from a memory controller, an amount of data transmitted or received to or from the memory controller, and/or a number of commands received from the memory controller. The remaining lifetime calculating device generates a remaining lifetime code representing a remaining lifetime of the semiconductor memory device based on the usage metrics, and stores the remaining lifetime code in the mode register.

A row hammer preventing circuitry including: a first table storing a count value representing a hit count and an address bit of multiple entries, each entry corresponding to access-requested target rows; a second table including safe bits and a safe bit counter; and a row hammer preventing logic to identify masking entries, on which a masking comparison is to be performed, among the entries on the basis of the safe bit counter, to determine a hit or miss on the basis of whether other bits except an MSB among address bits of an access-requested target row match other bits except an MSB among address bits of the masking entries, and to generate a control signal indicating an additional refresh on rows adjacent to rows corresponding to a masking entry whose hit count is greater than a threshold value.

Row addresses received by a module are mapped before being received by the memory devices of the module such that row hammer affects different neighboring row addresses in each memory device. Thus, because the mapped respective, externally received, row addresses applied to each device ensure that each set of neighboring rows for a given row address received by the module is different for each memory device on the module, row hammering of a given externally addressed row spreads the row hammering errors across different externally addressed rows on each memory device. This has the effect of confining the row hammer errors for each row that is hammered to a single memory device per externally addressed neighboring row. By confining the row hammer errors to a single memory device, the row hammer errors are correctible using a SDDC scheme.

Methods, systems, and devices for self-refresh of memory cells are described. A controller coupled with a memory cell may be configured to apply a first voltage to a control gate of a first transistor, where the first voltage activates the first transistor to selectively couple terminals of the first transistor with each other based on a charge stored on the interstitial gate. The controller may be configured to apply a current to a bit line, where a second voltage of the bit line is based on the current and the charge stored on the interstitial gate. The controller may be configured to apply, based on applying the first voltage to the control gate of the first transistor and applying the current to the bit line, a third voltage to a gate of a second transistor to couple the bit line with the interstitial gate of the first transistor.

A dynamic random access memory (DRAM) and an operation method thereof are provided. The DRAM includes a memory cell array, a refresh counter, a row hammer logic circuit, and a refresh logic circuit. The memory cell array includes a plurality of memory cell rows. The refresh counter provides a current refresh word line address. The row hammer logic circuit provides a victim word line address. The refresh logic circuit refreshes a target row during a first sub-period of a tRFC by using the current refresh word line address to perform an automatic refresh operation. The refresh logic circuit refreshes a victim row during a second sub-period of the same tRFC for row hammer protection by using the victim word line address.

A memory device may include: a memory bank comprising a first cell mat used as a normal area and a second cell mat used as a row hammer area and a redundancy area; a target address generation circuit suitable for: saving, in the row hammer area, a count of a received address for an active operation on the memory bank by performing an internal access operation on the row hammer area during the active operation, and setting, a particular count which satisfies a preset condition, an address corresponding to the particular count as a target address; a refresh control circuit suitable for controlling a smart refresh operation on the target address; and a column repair circuit suitable for repairing, when a bit line of the normal area has a defect, the bit line of the normal area with a bit line of the redundancy area.

A method for performing a refresh operation based on system characteristics is provided. A The method includes determining that a current operation condition of a memory component is in a first state and detecting a change in the operation condition from the first state to a second state. The method further includes determining a range of the operation condition to which the second state belongs. The method further includes determining a refresh period associated with the range of the operation condition, the refresh period corresponding to a period of time between a first time when a write operation is performed on a segment of the memory component and a second time when a refresh operation is to be performed on the segment. The method further includes performing the refresh operation on the memory component according to the refresh period.