Self-rectifying RRAM element

摘要

The disclosed technology generally relates to semiconductor devices and more particularly to memory devices having a resistance switching element, and to methods of operating such memory devices. In one aspect, a memory cell includes a first electrode and a second electrode formed of one of a metallic material or a semiconducting material. The memory cell additionally includes a resistance switching element formed between the first electrode and the second electrode. The memory cell additionally includes a tunnel rectifier formed between the resistance-switching element and the first electrode. The tunnel rectifier includes a multi-layer tunnel stack comprising at least two dielectric layers each having a dielectric constant (ki), a conduction band offset (Φi), and a thickness, wherein one of the dielectric layers has a higher dielectric constant, a lower conduction band offset and a higher thickness compared to any other dielectric layer of the multi-layer tunnel stack.

主权项

1. A memory cell comprising:
a first electrode and a second electrode formed of one of a metallic material or a semiconducting material; a resistance-switching element formed between the first electrode and the second electrode; a tunnel rectifier formed between and in physical contact with the resistance-switching element and the first electrode, wherein the tunnel rectifier comprises a multi-layer tunnel stack comprising at least two dielectric layers each having a dielectric constant (ki), a conduction band offset (Φi), and a thickness, and wherein the resistance-switching element is configured to switch between a low resistance state and a high resistance state in response to electrons tunneling through the tunnel rectifier, wherein one of the dielectric layers has a higher dielectric constant, a lower conduction band offset and a higher thickness compared to any other dielectric layer of the multi-layer tunnel stack, wherein the dielectric constant of one of the dielectric layers does not exceed 12 and a dielectric constant of another one of the dielectric layers is between about 20 and about 50, wherein the multi-layer tunnel stack is a stack of three dielectric layers, wherein a dielectric layer is sandwiched between a first neighboring dielectric layer and a second neighboring dielectric layer and has: a dielectric constant (k2) that is higher than dielectric constants of the first and second neighboring dielectric layers (k2>k1 and k2>k3); a conduction band offset (Φ2) that is lower than conduction band offsets of the first and second neighboring dielectric layers (Φ2−Φ1 and Φ2<Φ3); and a thickness (t2) that is higher than thicknesses of the first and second neighboring dielectric layers (t2>t1 and t2>t3).