Random number generation using threshold switching mechanism

Patent metadata

Field	Value
Publication number	US-9910639-B2
Application number	US-201514953730-A
Country	US
Kind code	B2
Filing date	Nov 30, 2015
Priority date	Nov 30, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

Embodiments include a random number generation entity having at least one switching cell comprising a pair of electrodes and a chalcogenide layer arranged between the pair of electrodes and a pulse generating entity coupled with the electrodes of the switching cell. The pulse generating entity is configured to provide an excitation pulse to the switching cell. The random number generation entity also includes a detection entity configured to provide a detection signal indicating whether an electrical property measured at the switching cell exceeds or falls below a threshold value due to applying the excitation pulse to the switching cell and a random number generation entity adapted to generate a random number based on the detection signal of the detection entity.

First claim

The invention claimed is:

1. A random number generation entity comprising:
a switching cell comprising a pair of electrodes and a chalcogenide layer arranged between the pair of electrodes;
a pulse generating entity coupled with the electrodes of the switching cell, the pulse generating entity being configured to provide an excitation pulse to the switching cell;
a detection entity configured to provide a detection signal indicating whether an electrical property measured at the switching cell exceeds or falls below a threshold value due to applying the excitation pulse to the switching cell; and
a random number generation entity adapted to generate a random number based on the detection signal of the detection entity,
wherein the switching cell comprises a voltage-current-characteristic with a sub-threshold area and a current jump above the sub-threshold area, wherein the pulse generating entity is configured to provide an excitation pulse with a voltage level such that an electrical current through the switching cell exceeds the sub-threshold area.

2. The random number generation entity of claim 1 , the chalcogenide layer comprising GeTe, SbTe, GeSb, GeSbTe, AgInSbTe, GaSb, Sb, AsTeGeSi, AsTeGe, AsSeGe, GeSe or ZnTe, including a doping of using Si, N, SiO 2 and C.

3. The random number generation entity of claim 1 , the pulse generating entity being configured to provide an excitation pulse with a voltage level such that the chalcogenide layer shows a drop of electrical resistance from a higher resistance level to a lower resistance level as a stochastic process.

4. The random number generation entity of claim 1 , the pulse generating entity being adapted to choose the voltage level and/or the pulse duration of the excitation pulse in order to obtain a desired probability of exceeding a given current threshold value.

5. The random number generation entity of claim 1 , the pulse generating entity being adapted to choose the voltage level and/or the pulse duration of the excitation pulse such that, after providing the excitation pulse to the switching cell, the electrical resistance of the switching cell returns to the initial value without external influence.

6. The random number generation entity of claim 1 , the pulse generating entity being adapted to choose the voltage level and/or the pulse duration of the excitation pulse such that, even after terminating the excitation pulse, the electrical resistance of the switching cell remains in a low electrical resistance state.

7. The random number generation entity of claim 6 , the pulse generating entity being adapted to provide a reset pulse to the switching cell in order to reset the switching cell into a high electrical resistance state.

8. The random number generation entity of claim 1 , the pulse generating entity being adapted to provide multiple consecutive excitation pulses to the switching cell in order to generate a binary number comprising multiple bits.

9. The random number generation entity of claim 1 , comprising multiple switching cells in parallel, the switching cells being coupled with a common pulse generating entity.

10. The random number generation entity of claim 1 , the switching cell being coupled in series with a resistive memory element adapted to store switching state based on structural change of the material properties.

11. The random number generation entity of claim 1 , comprising a bias check entity adapted to control the voltage level and/or the pulse duration of the excitation pulse such that a desired probability of exceeding the current threshold value is achieved.

12. The random number generation entity of claim 1 , comprising a bias tuning entity adapted to change the voltage level and/or the pulse duration of the excitation pulse according to environment parameters.

13. A random number generator switching arrangement comprising:
a switching cell comprising a pair of electrodes and a chalcogenide layer arranged between the pair of electrodes;
a pulse generating entity coupled with the electrodes of the switching cell, the pulse generating entity being configured to provide an excitation pulse to the switching cell in order to trigger a stochastic threshold switching process,
wherein the switching cell comprising a voltage-current-characteristic with a sub-threshold area and a current jump above the sub-threshold area, the pulse generating entity being configured to provide an excitation pulse with a voltage level such that an electrical current through the switching cell exceeds the sub-threshold area.

14. The random number generation entity of claim 13 , the chalcogenide layer comprising GeTe, SbTe, GeSb, GeSbTe, AgInSbTe, GaSb, Sb, AsTeGeSi, AsTeGe, AsSeGe, GeSe or ZnTe, including a doping of using Si, N, SiO 2 and C.

15. The random number generation entity of claim 13 , the pulse generating entity being configured to provide a excitation pulse with a voltage level such that the chalcogenide layer shows a drop of electrical resistance from a higher resistance level to a lower resistance level as a stochastic process.

16. The random number generation entity of claim 13 , the pulse generating entity being adapted to choose the voltage level and/or the pulse duration of the excitation pulse in order to obtain a desired probability of exceeding a given current threshold value.

17. The random number generation entity of claim 13 , the pulse generating entity:
being adapted to choose the voltage level and/or the pulse duration of the excitation pulse such that, after providing the excitation pulse to the switching cell, the electrical resistance of the switching cell returns to the initial value without external influence; or
being adapted to choose the voltage level and/or the pulse duration of the excitation pulse such that, even after terminating the excitation pulse, the electrical resistance of the switching cell remains in a low electrical resistance state and the pulse generating entity is adapted to provide a reset pulse to the switching cell in order to reset the switching cell into a high electrical resistance state.

18. A Method for generating random numbers, the method comprising:
providing an excitation pulse to a switching cell, the switching cell comprising a pair of electrodes and a chalcogenide layer arranged between the pair of electrodes;
detecting whether an electrical property measured at the switching cell exceeds or falls below a threshold value due to applying the excitation pulse to the switching cell thereby obtaining a detection signal; and
generating a random number based on the detection signal,
wherein the switching cell comprises a voltage-current-characteristic with a sub-threshold area and a current jump above the sub-threshold area, wherein the pulse generating entity is configured to provide an excitation pulse with a voltage level such that an electrical current through the switching cell exceeds the sub-threshold area.

Assignees

• IBM

Inventors

• Le Gallo Manuel
• Sebastian Abu

Classifications

• G11C13/0004

  comprising amorphous/crystalline phase transition cells · CPC title

• G06F2207/58

  Indexing scheme relating to groups G06F7/58 - G06F7/588 · CPC title

• H01L27/01

  Electricity · mapped topic

• G06F7/588 Primary

  Random number generators, i.e. based on natural stochastic processes · CPC title

• H01J3/00

  Details of electron-optical or ion-optical arrangements common to two or more basic types of discharge tubes or lamps · CPC title