Programming method for programming flash memory array structure
The invention provides a flash memory array structure and a method for programming the same, which relates to a technical field of nonvolatile memories in ultra large scale integrated circuit fabrication technology. The flash memory array of the present invention includes memory cells, word lines and bit lines connected to the memory cells, wherein the word lines connected to control gates of the memory cells and the bit lines connected to drain terminals of the memory cells are not perpendicular to each other but cross each other at an angle; the control gates of two memory cells adjacent to each other along the channel direction between every two bit lines are controlled by two word lines, respectively, drain terminals thereof are controlled by two bit lines, respectively, and source terminals thereof are shared. The present invention also provides a method for programming the flash memory array structure, which can realize a programming with low power consumption.
1. A programming method for programming a flash memory array structure comprising:
a plurality of memory cells constituting an array, wherein word lines and bit lines cross each other but are not perpendicular to each other; each of the word lines is connected to control gates of all the memory cells in a same row of the array; each of the bit lines is connected to drain terminals of all the memory cells in a same column; and every two memory cells adjacent to each other along a channel direction share a source terminal,
the programming method characterized in that: a programming is performed by involving both of two memory cells adjacent to each other along a channel direction between two adjacent bit lines and connected in series, wherein one bit line is grounded and a high bit line programming voltage is applied to the other bit line, and the common source terminal is floating, while the control gates of the two memory cells are connected to two word lines, respectively, and different voltages are applied to the two word lines when the programming is performed.
2. The programming method according to claim 1 , characterized in that, a voltage of 3-5V is applied to the bit line of the selected memory cell, a voltage of 7-10V is applied to the word line of the selected memory cell, and the source terminal of the selected memory cell is floating.
3. The programming method according to claim 2 , characterized in that, the bit line of the memory cell adjacent to and connected in series with the selected memory cell is grounded, and a voltage of 3-7V is applied to the word line thereof.
4. The programming method according to claim 1 , characterized in that, the control gates of two memory cells adjacent to each other along the channel direction between two bit lines are controlled by two adjacent word lines, respectively, drain terminals thereof are controlled by two bit lines, respectively, and source terminals thereof are shared.
5. The programming method according to claim 1 , characterized in that, the memory cells are floating-gate-type flash memory cells or trapping-type flash memory cells.