Nonvolatile memory cell without a dielectric antifuse having high- and low-impedance states

摘要

A memory cell according to the present invention comprises a bottom conductor, a doped semiconductor pillar, and a top conductor. The memory cell does not include a dielectric rupture antifuse separating the doped semiconductor pillar from either conductor, or within the semiconductor pillar. The memory cell is formed in a high-impedance state, in which little or no current flows between the conductors on application of a read voltage. Application of a programming voltage programs the cell, converting the memory cell from its initial high-impedance state to a low-impedance state. A monolithic three dimensional memory array of such cells can be formed, comprising multiple memory levels, the levels monolithically formed above one another.

主权项

1. A programmable memory cell comprising:
a first conductor extending in a first direction; a vertical pillar consisting essentially of semiconductor material and conductivity-enhancing dopants and having a top surface and a bottom surface; and a second conductor above the first conductor extending in a second direction different from the first direction, wherein: the vertical pillar is disposed between the first and second conductors, the top surface and the bottom surface are in electrical contact with the first and second conductors, the vertical pillar comprises a silicon-germanium alloy and has a bottom region and a center region, the bottom region having a higher ratio of silicon to germanium than the center region, no dielectric rupture antifuse is disposed between the first and second conductors, and the programmable memory cell has a high impedance state and conducts unprogrammed current during application of a read voltage and has a low impedance state and conducts programmed current after application of a programming voltage and then the read voltage.