Semiconductor device and method of forming thereof

A method comprising:

• forming a bottom electrode in a first inter-metal dielectric (IMD) layer;
• forming an insulation film over a recessed region in the bottom electrode;
• forming a resistance switchable layer over the insulation film and in contact with inner sidewalls of the recessed region in the bottom electrode;
• forming a top electrode over the resistance switchable layer;
• etching the bottom electrode and the resistance switchable layer to form a recess around the top electrode;
• and
• forming an etch stop layer filling up the recess around the top electrode.

A semiconductor device, comprising:

• a first inter-metal dielectric (IMD) layer;
• a first metal line in the first IMD layer;
• a second IMD layer;
• a second metal line in the second IMD layer;
• a third IMD layer between the first and second IMD layer;
• and
• a resistive random access memory (RRAM) cell embedded in the third IMD layer, comprising:
• a bottom electrode having a first portion extending laterally along a top surface of the first metal line and second portions extending along sidewalls of the third IMD layer;
• an insulation film covering at least a partial region of the first portion of the bottom electrode;
• a resistance switchable layer over the insulation film and in contact with inner sidewalls of the second portions of the bottom electrode;
• a top electrode over the resistance switchable layer and in contact with the second metal line;
• and
• a dielectric layer around the top electrode, wherein the second metal line is spaced apart from the bottom electrode and the resistance switchable layer by the dielectric layer.