Method of fabricating resistive random access memory cell

A method of fabricating a resistive random access memory cell, comprising:

• forming a stacked layer alternately stacked by a plurality of first conductive layers and a plurality of first sacrificial layers on a first dielectric layer;
• patterning the stacked layer to form a patterned stacked layer;
• forming a second sacrificial layer around the patterned stacked layer;
• forming an opening passing through the plurality of first conductive layers and the plurality of first sacrificial layers in the patterned stacked layer;
• forming a second conductive layer in the opening, wherein the second conductive layer and the plurality of first conductive layers form a first electrode layer;
• removing the plurality of first sacrificial layers and the second sacrificial layer;
• forming a variable resistance layer and an oxygen reservoir layer on a surface of the first electrode layer and a top surface of the first dielectric layer;
• patterning the oxygen reservoir layer to form a patterned oxygen reservoir layer and expose the variable resistance layer;
• forming a second dielectric layer on the variable resistance layer and the patterned oxygen reservoir layer;
• and
• forming a second electrode in the second dielectric layer, wherein the second electrode covers a top surface and an upper sidewall of the patterned oxygen reservoir layer.