Memory using variable tunnel barrier widths

An erased two-terminal memory cell, comprising:

• a two-terminal memory element configured to store non-volatile data as an erased conductivity and including electrically in series with one another
• an ion reservoir including a plurality of first mobile ions having a first electric charge and a first ion mobility,
• a complementary ion reservoir including a plurality of second mobile ions having a second electric charge and a second ion mobility, the second electric charge is opposite in polarity to the first electric charge and the plurality of second mobile ions are a different ion type than the plurality of first mobile ions,
• a tunnel barrier layer in contact with the ion reservoir and the complementary ion reservoir and having a first thickness that is approximately 50 Å or less and operative to define a variable tunnel barrier thickness, and
• wherein the memory element stores the non-volatile data as the erased conductivity when the variable tunnel barrier thickness comprises the first thickness.

A re-writeable non-volatile memory device, comprising:

• a plurality of two-terminal memory cells arranged in a two-terminal cross-point array configuration with a first terminal of each memory cell electrically coupled with only one of a plurality of first conductive array lines and a second terminal of each memory cell electrically coupled with only one of a plurality of second conductive array lines, each memory cell configured to store non-volatile data as a programmed conductivity or an erased conductivity, and each memory cell including electrically in series with one another
• an ion reservoir including a plurality of first mobile ions having a first electric charge and a first ion mobility,
• a complementary ion reservoir including a plurality of second mobile ions having a second electric charge and a second ion mobility, the second electric charge is opposite in polarity to the first electric charge and the plurality of second mobile ions are a different ion type than the plurality of first mobile ions,
• a tunnel barrier layer in contact with the ion reservoir and the complementary ion reservoir and having a first thickness when the memory cell stores data as the programmed conductivity or the erased conductivity, and
• a low conductivity region present in the memory cell only when the memory cell stores data as the programmed conductivity, the low conductivity region comprised of accumulated mobile ions and having a second thickness that is substantially less than the first thickness, the first thickness and second thickness cumulatively form a variable tunnel barrier thickness that is approximately 50 Å or less, the low conductivity region is positioned either in the ion reservoir adjacent to an interface between the ion reservoir and the tunnel barrier layer or in the complementary ion reservoir adjacent to an interface between the complementary ion reservoir and the tunnel barrier layer,
• wherein each memory cell stores the non-volatile data as the programmed conductivity when the variable tunnel barrier thickness comprises the first thickness and second thickness,
• wherein each memory cell stores the non-volatile data as the erased conductivity when the variable tunnel barrier thickness comprises only the first thickness;
• and
• a substrate including active circuitry fabricated on the substrate, at least a portion of the active circuitry is electrically coupled with the plurality of first and second conductive array lines and operative to apply voltages across selected conductive array lines during read and write operations, the two-terminal cross-point array is in contact with the substrate and is fabricated directly over the substrate.