US 7,352,631 B2 · Methods for programming a floating body nonvolatile memory

Abstract

A technique to speed up the programming of a non-volatile memory device that has a floating body actively removes holes from the floating body that have accumulated after performing hot carrier injection (HCI). The steps of HCI and active hole removal can be alternated until the programming is complete. The active hole removal is faster than passively allowing holes to be removed, which can take milliseconds. The active hole removal can be achieved by reducing the drain voltage to a negative voltage and reducing the gate voltage as well. This results in directly withdrawing the holes from the floating body to the drain. Alternatively, reducing the drain voltage while maintaining current flow stops impact ionization while sub channel current collects the holes. Further alternatively, applying a negative gate voltage causes electrons generated by band to band tunneling and impact ionization near the drain to recombine with holes.

Claims18

Dependent claims

A method of programming a non-volatile memory (NVM) cell having a floating body, comprising

during a first programming phase:
applying a voltage at a first level to a drain of the NVM cell;
applying a voltage at a second level to a source of the NVM cell, wherein the second level is lower than the first level;
and
applying a voltage at a third level to a gate of the NVM cell, wherein the third level is greater than the second level;
and
during a second programming phase after the first programming phase, performing one of the following steps to remove holes in the floating body:
reducing the voltage on the drain to a fourth level, wherein current flows between the source and drain and wherein the fourth level is sufficiently low so as to result in minimal impact ionization;
reducing the voltage on the gate to a fifth level, wherein the fifth level is lower than the second level;
or
reducing the voltage on the drain to a sixth level and reducing the voltage on the gate, wherein the sixth level is below the second level.

8 more elements

Dependencies are inferred from the claim text.

Methods for programming a floating body nonvolatile memory

Life of this patent

Methods for programming a floating body nonvolatile memory

Life of this patent

Abstract

Claims18