Semiconductor memory device including shorted variable resistor element of memory cell

Abstract

A semiconductor memory device includes a shorted variable resistor element in a memory cell. The semiconductor memory device includes main cells and reference cells each including a cell transistor and a variable resistor element. The variable resistor element of the reference cell is shorted by applying a breakdown voltage of a magnetic tunnel junction (MTJ) element, connection in parallel to a conductive via element, connection to a reference bit line at a node between the cell transistor and the variable resistor element, or replacement of the variable resistor element with the conductive via element. A sense amplifier increases a sensing margin of the main cell by detecting and amplifying a current flowing in a bit line of the main cell and a current flowing in the reference bit line to which a reference resistor is connected.