Systems for margined neighbor reading for non-volatile memory read operations including coupling compensation
AssigneeSanDisk Corporation
InventorNima Mokhlesi
Life of this patent
Estimating the term…
Abstract
Shifts in the apparent charge stored on a floating gate (or other charge storing element) of a non-volatile memory cell can occur because of the coupling of an electric field based on the charge stored in adjacent floating gates (or other adjacent charge storing elements). The problem occurs most pronouncedly between sets of adjacent memory cells that have been programmed at different times. To account for this coupling, the read process for a particular memory cell will provide compensation to an adjacent memory cell in order to reduce the coupling effect that the adjacent memory cell has on the particular memory cell. When reading the adjacent cell to determine the appropriate compensation, margined read voltages can be used.
Claims31
A non-volatile memory system, comprising:
- a plurality of non-volatile storage elements;
- and
- managing circuitry in communication with said plurality of non-volatile storage elements that performs a read process for a selected non-volatile storage element connected to a selected word line, said managing circuitry applies a read voltage corresponding to a particular state to an unselected non-volatile storage element at a first voltage level to determine a state of said unselected non-volatile storage element, applies said read voltage to said selected non-volatile storage element at a second voltage level during said read process, uses a particular voltage for said unselected non-volatile storage element when applying said read voltage to said selected non-volatile storage element based on said state of said unselected non-volatile storage element, and senses a condition of said selected non-volatile storage element during said read process, said first voltage level is lower than said second voltage level.
A non-volatile memory system, comprising:
- a plurality of non-volatile storage elements including a first non-volatile storage element, a second non-volatile storage element, and a third non-volatile storage element, said second non-volatile storage element is adjacent to said first non-volatile storage element in a first direction, said third non-volatile storage element is adjacent to said first non-volatile storage element in a second direction;
- and
- managing circuitry in communication with said plurality of non-volatile storage elements, said managing circuitry provides a first pass voltage to said first non-volatile storage element when verifying programming of said second non-volatile storage element, provides a second pass voltage to said first non-volatile storage element when determining a current condition of said second non-volatile storage element during a read process for said third non-volatile storage element, provides a first read voltage corresponding to a particular state to said second non-volatile storage element when determining said current condition, and provides a second read voltage corresponding to said particular state to said third non-volatile storage element to determine a condition of said third non-volatile storage element during said read process, said first read voltage is based on a difference between said first pass voltage and said second pass voltage, said first read voltage is lower than said second read voltage.
A non-volatile memory system, comprising:
- a plurality of non-volatile storage elements;
- and
- managing circuitry in communication with said plurality of non-volatile storage elements, said managing circuitry applies a first read compare voltage corresponding to a first state to an unselected non-volatile storage element as part of reading a selected non-volatile storage element that neighbors said unselected non-volatile storage element, applies a second read compare voltage corresponding to said first state to said selected non-volatile storage element being read, applies a first read pass voltage to said unselected non-volatile storage element, applies a second read pass voltage to a different unselected non-volatile storage element, and senses a condition of said selected non-volatile storage element being read while applying said first read pass voltage and said second read pass voltage, said first read compare voltage is lower than said second read compare voltage.
Dependencies are inferred from the claim text.