Non-volatile memory with adjustable cell bit shape
View Patent ↗Embodiments of the present disclosure generally relate to non-volatile memory and, in particular, non-volatile memory with adjustable cell bit shapes. In one embodiment, an adjustable memory cell is provided. The memory cell generally includes a gate electrode, at least one recording layer and a channel layer. The channel layer generally is capable of supporting a depletion region and is disposed between the gate electrode and the at least one recording layer. In this embodiment, upon activating the gate, the channel layer may be depleted and current initially flowing through the channel may be steered through the at least one recording layer.
1. A method for recording one or more bits in at least one memory cell, comprising:
applying a current to a channel layer of the at least one memory cell;
activating a gate of the at least one memory cell by applying a voltage to the gate of the at least one memory cell;
upon activating the gate, depleting the channel layer in order to channel the current from the channel layer into a recording layer of the at least one memory cell, wherein the recording layer is in a first resistance state; and
transforming at least one portion of the recording layer from the first resistance state to a second resistance state in order to write one or more bits into the recording layer, wherein the first resistance state and the second resistance state are different, and wherein at least one of a size or shape of the at least one transformed portion of the recording layer is controlled, in part, by the voltage applied to the gate and the current applied into the channel layer.
2. The method of claim 1 , wherein the recording layer comprises one of phase change material or resistive random access memory material.
3. The method of claim 1 , wherein transforming the at least one portion of the recording layer to write one or more bits comprises transforming a first portion of the at least one portion to a resistance state and transforming a second portion of the at least one portion to a different resistance state, wherein each transformed portion corresponds to a recorded bit.
4. The method of claim 1 , wherein controlling the at least one of the size and shape of the at least one transformed portion comprises controlling a width of the at least one transformed portion by applying a constant voltage to the gate and varying the current applied to the channel layer.
5. The method of claim 1 , wherein controlling the at least one of the size or shape of the at least one transformed portion comprises controlling a depth of the at least one transformed portion by varying a voltage applied to the gate of the at least one memory cell and varying a current applied to the channel of the at least one memory cell.
6. The method of claim 1 , wherein the at least one memory cell comprises a plurality of memory cells connected in a string.
7. The method of claim 6 , further comprising:
sequentially writing to each of the plurality of memory cells one at a time by turning off the gates of any memory cells not being written to.
8. The method of claim 6 , further comprising:
simultaneously writing to each of the plurality of memory cells by applying a constant current signal and varying the voltage applied to each of the plurality of memory cells.
9. The method of claim 1 , further comprising, upon activating the gate:
extending the depletion of the channel layer into the recording layer of the at least one memory cell; and
controlling a depth of the extension of the depletion into the recording layer, based on the voltage applied to the gate, in order to write one or more bits.
10. The method of claim 9 , further comprising:
encoding a plurality of resistance topologies based on a number of the one or more bits written into the recording layer.
11. The method of claim 1 , wherein controlling the at least one of the size or shape of the at least one transformed portion comprises controlling a depth of the at least one transformed portion by varying at least one of a time that a voltage is applied to the gate of the at least one memory cell and a time that a current is applied to the channel of the at least one memory cell.
12. An adjustable non-volatile memory cell, comprising:
a gate;
at least one recording layer; and
a channel layer, capable of supporting a depletion region, disposed between the gate and the at least one recording layer, wherein current is initially flowing through the channel layer, wherein upon activating the gate, the channel layer is depleted and the current initially flowing the channel layer is steered through the at least one recording layer, wherein a portion of the at least one recording layer is capable of being transformed from a first resistance state to a second resistance state, based on the current steered through the at least one recording layer, and wherein at least one of a size or shape of the transformed portion is capable of being controlled in order to store at least one bit.
13. The adjustable non-volatile memory cell of claim 12 , wherein a plurality of portions of the at least one recording layer are capable of being transformed from a first resistance state to a second resistance state, based on a sequence of current signals steered through the at least one recording layer, and wherein at least one of a size or shape of each of the plurality of transformed portions is capable of being controlled in order to store a plurality of bits.
14. The adjustable non-volatile memory cell of claim 13 , wherein a width of each of the plurality of transformed portions is capable of being controlled by a constant voltage applied to the gate and a varying current sequence applied to the channel layer.
15. The adjustable non-volatile memory cell of claim 13 , wherein a depth of each of the plurality of transformed portions is capable of being controlled by a varying current sequence applied to the channel layer and a varying voltage applied to the gate.
16. The adjustable non-volatile memory cell of claim 12 , wherein the at least one recording layer is capable of supporting a depletion region.
17. The adjustable non-volatile memory cell of claim 16 , wherein a plurality of portions of the at least one recording layer are capable of being transformed from a first resistance state to a second resistance state based on extension of a depth of the depletion region into the at least one recording layer.
18. The adjustable non-volatile memory cell of claim 12 , wherein the at least one recording layer comprises at least one of phase change material and resistive random access memory material.
19. The adjustable non-volatile memory cell of claim 12 , wherein the at least one recording layer comprises a plurality of layers, each layer having different material properties.
20. A system, comprising:
a plurality of memory cells;
a processor configured to address each of the plurality of memory cells, wherein, for each of the plurality of memory cells, the processor is configured to:
apply a current to a channel layer of the memory cell;
activate a gate of the memory cell by applying a voltage to the gate of the memory cell;
upon activating the gate, channeling the current from the channel layer into a recording layer of the memory cell, wherein the recording layer is in a first resistance state; and
transform at least one portion of the recording layer from the first resistance state to a second resistance state in order to write one or more bits into the recording layer, wherein the first resistance state and the second resistance state are different, and wherein at least one of a size or shape of the at least one transformed portion of the recording layer is controlled, in part, by the voltage applied to the gate and the current applied into the channel layer.