Memory cell comprising switchable semiconductor memory element with trimmable resistance
First Claim
1. A method for changing and sensing data states for a nonvolatile memory cell, the method comprising:
- switching silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of a semiconductor diode from a first stable resistivity state to a second stable resistivity state, the second resistivity state lower resistivity than the first resistivity state;
switching the silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of the semiconductor diode from the second stable resistivity state to a third stable resistivity state, the third resistivity state higher resistivity than the second resistivity state; and
sensing the first resistivity state, the second resistivity state, or the third resistivity state as a data state of the memory cell,wherein;
the semiconductor diode consists essentially of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material;
at least a portion of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material is doped;
the memory cell comprises a portion of a first conductor;
a portion of a second conductor; and
a switchable memory element comprising the silicon or silicon alloy, or germanium or germanium alloy semiconductor material of the semiconductor diode, the switchable memory element disposed between the first and second conductors;
the semiconductor diode in the first stable resistivity state has a first resistivity when a read voltage is applied to the semiconductor diode;
the semiconductor diode in the second stable resistivity state has a second resistivity when the read voltage is applied to the semiconductor diode;
the semiconductor diode in the third stable resistivity state has a third resistivity when the read voltage is applied to the semiconductor diode; and
the first resistivity, the second resistivity, and the third resistivity are different from each other.
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Accused Products
Abstract
A nonvolatile memory cell comprising doped semiconductor material and a diode can store memory states by changing the resistance of the doped semiconductor material by application of a set pulse (decreasing resistance) or a reset pulse (increasing resistance.) Set pulses are of short duration and above a threshold voltage, while reset pulses are longer duration and below a threshold voltage. In some embodiments multiple resistance states can be achieved, allowing for a multi-state cell, while restoring a prior high-resistance state allows for an rewriteable cell. In some embodiments, the diode and a switchable memory formed of doped semiconductor material are formed in series, while in other embodiments, the diode itself serves as the semiconductor switchable memory element.
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Citations
19 Claims
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1. A method for changing and sensing data states for a nonvolatile memory cell, the method comprising:
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switching silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of a semiconductor diode from a first stable resistivity state to a second stable resistivity state, the second resistivity state lower resistivity than the first resistivity state; switching the silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of the semiconductor diode from the second stable resistivity state to a third stable resistivity state, the third resistivity state higher resistivity than the second resistivity state; and sensing the first resistivity state, the second resistivity state, or the third resistivity state as a data state of the memory cell, wherein; the semiconductor diode consists essentially of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material; at least a portion of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material is doped; the memory cell comprises a portion of a first conductor;
a portion of a second conductor; and
a switchable memory element comprising the silicon or silicon alloy, or germanium or germanium alloy semiconductor material of the semiconductor diode, the switchable memory element disposed between the first and second conductors;the semiconductor diode in the first stable resistivity state has a first resistivity when a read voltage is applied to the semiconductor diode; the semiconductor diode in the second stable resistivity state has a second resistivity when the read voltage is applied to the semiconductor diode; the semiconductor diode in the third stable resistivity state has a third resistivity when the read voltage is applied to the semiconductor diode; and the first resistivity, the second resistivity, and the third resistivity are different from each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for changing data states for a nonvolatile memory cell, the method comprising:
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switching silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of a semiconductor diode from a first stable resistivity state to a second stable resistivity state, the second resistivity state lower resistivity than the first resistivity state, and switching the silicon or a silicon alloy, or germanium or a germanium alloy semiconductor material of the semiconductor diode from the second resistivity state to a third stable resistivity state, the third resistivity state lower resistivity than the second resistivity state, wherein; the semiconductor diode consists essentially of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material; at least some portion of the silicon or silicon alloy, or germanium or germanium alloy semiconductor material is doped; the memory cell consists of a portion of a first conductor;
a portion of a second conductor; and
the semiconductor diode that functions as a switchable memory element, disposed between the portion of the first conductor and the portion of the second conductor;the semiconductor diode in the first stable resistivity state has a first resistivity when a read voltage is applied to the semiconductor diode; the semiconductor diode in the second stable resistivity state has a second resistivity when the read voltage is applied to the semiconductor diode; the semiconductor diode in the third stable resistivity state has a third resistivity when the read voltage is applied to the semiconductor diode; and the first resistivity, the second resistivity, and the third resistivity are different from each other. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification