Bipolar decoders for nonvolatile memory with spike attenuation for threshold selector switches

Abstract

For MRAM and other memory cell technologies that use threshold selector switches such as ovonic threshold switches, when accessing a selected memory cell, such as for a read, the voltage across the memory cell needs to be sufficient to turn on the threshold selector switch. This results in a current spike that can damage the memory cell and disturb a data value written in it. To reduce such spikes, the local select switches biasing to the selected word line and selected bit line can be biased to limit the current flow from the decoding circuitry when the threshold selector switch turns on.