Resistively switching memory
The present invention relates to a reproducible conditioning during the manufacturing of a resistively switching CBRAM memory cell comprising a first electrode and a second electrode with an active material positioned therebetween. The active material is adapted to be placed in a more or less electroconductive state by means of electrochemical switching processes. A CBRAM memory cell manufactured pursuant to the method according to the invention has, due to the improved conditioning, more reliable and more distinctly evaluable electrical switching properties. Moreover, no more forming step is necessary with the method according to the present invention.
1. A method for manufacturing a resistively switching memory cell, comprising a first electrode and a second electrode with an active material positioned therebetween, the active material being adapted to be placed in a substantially electroconductive state by means of electrochemical switching processes, comprising:
doping the active material in a doping process by diffusing a mobile material into the active material from the first electrode in a direction to the second electrode to build a doped region; and
performing a retraction process by at least partial retraction of the mobile material diffused into the active material from a region close to the second electrode to generate or modify a doping profile between the doped region and an undoped region, wherein performing the retraction process comprises applying an electric charge to the electrodes by contact with a high frequency inert gas plasma.
2. The method according to claim 1 , wherein the doping process further comprises:
doping the active material by diffusing a mobile material into the active material in a doping process; and
overdoping the active material by diffusing the mobile material into the active material in an overdoping process exceeding the prior doping, such that, in the active material, a doped region is formed from the first electrode up to the second electrode.
3. The method according to claim 1 , wherein at least one of the doping process and the overdoping process is performed such that the mobile material is diffused into the active material from the first electrode up to the second electrode.
4. The method according to claim 1 , wherein the active material comprises a chalcogenide compound, consisting of a GeSe, GeS, AgSe, or a CuS compound, and wherein the mobile material comprises alkali ions or metal ions, respectively, consisting of Ag, Zn, or Cu.
5. The method according to claim 1 , wherein the mobile material diffused into the active material diffuses back at least partially from the active material during the retraction process.
6. The method according to claim 1 , wherein a doped or overdoped phase and an undoped phase are formed in the active material.
7. The method according to claim 6 , wherein a particular penetration depth of the mobile material into the active material, in a region between the doped or overdoped phase and the undoped phase in the active material, is achieved.
8. The method according to claim 6 , wherein a particular concentration profile of the mobile material is formed in the active material, in a region between the doped or overdoped phase and the undoped phase in the active material.
9. The method according to claim 1 , wherein the mobile material is diffused into the active material or diffused back, respectively, with an electric charge of appropriate polarity that is applied from outside preferably via the electrodes.
10. The method according to claim 1 , wherein the active material is preconditioned preferably by means of photo diffusion.
11. The method according to claim 1 , wherein self-adjusting processes are used in which different lithography levels do not comprise any misadjustment with respect to one another.
12. A method for manufacturing a resistively switching memory cell, comprising a first electrode and a second electrode with an active material positioned therebetween, the active material being adapted to be placed in a substantially electroconductive state by means of electrochemical switching processes, comprising:
doping the active material in a doping process by diffusing a mobile material into the active material from the first electrode in a direction to the second electrode to build a doped region; and
performing a retraction process by at least partial retraction of the mobile material diffused into the active material from a region close to the second electrode to generate or modify a doping profile between the doped region and an undoped region, wherein performing the retraction process comprises applying an electric charge to the electrodes by inert gas ion beams.
13. The method according to claim 12 , wherein the doping process further comprises:
doping the active material by diffusing a mobile material into the active material in a doping process; and
overdoping the active material by diffusing the mobile material into the active material in an overdoping process exceeding the prior doping, such that, in the active material, a doped region is formed from the first electrode up to the second electrode.
14. The method according to claim 12 , wherein at least one of the doping process and the overdoping process is performed such that the mobile material is diffused into the active material from the first electrode up to the second electrode.
15. The method according to claim 12 , wherein the active material comprises a chalcogenide compound, consisting of a GeSe, GeS, AgSe, or a CuS compound, and wherein the mobile material comprises alkali ions or metal ions, respectively, consisting of Ag, Zn, or Cu.
16. The method according to claim 12 , wherein the mobile material diffused into the active material diffuses back at least partially from the active material during the retraction process.
17. The method according to claim 12 , wherein a doped or overdoped phase and an undoped phase are formed in the active material.
18. The method according to claim 17 , wherein a particular penetration depth of the mobile material into the active material, in a region between the doped or overdoped phase and the undoped phase in the active material, is achieved.
19. The method according to claim 17 , wherein a particular concentration profile of the mobile material is formed in the active material, in a region between the doped or overdoped phase and the undoped phase in the active material.
20. The method according to claim 12 , wherein the mobile material is diffused into the active material or diffused back, respectively, with an electric charge of appropriate polarity that is applied from outside preferably via the electrodes.
21. The method according to claim 12 , wherein the active material is preconditioned preferably by means of photo diffusion.
22. The method according to claim 12 , wherein self-adjusting processes are used in which different lithography levels do not comprise any misadjustment with respect to one another.