Semiconductor device, memory cell and method of forming the same

A semiconductor device, comprising:

• a first interconnect structure disposed on a substrate;
• at least one memory cell disposed on the first interconnect structure, wherein the at least one memory cell comprises:
• a bottom electrode connected to the first interconnect structure;
• a first memory element disposed on the bottom electrode;
• a connecting structure disposed on the first memory element, wherein the connecting structure comprises:
• a base portion connected to the first memory element;
• and
• a pillar portion protruding out from the base portion, wherein a width of the pillar portion approximate to the base portion is wider than tops of the pillar portion away from the base portion;
• a selector disposed on and connected to the pillar portion;
• and
• a top electrode disposed on the selector;
• and
• a second interconnect structure disposed on the at least one memory cell and electrically connected to the top electrode.

A method of forming a memory cell, comprising:

• providing a bottom electrode;
• providing a memory material stack on the bottom electrode, and a connecting material on the memory material stack;
• performing a first patterning process on the connecting material to define a base portion and a pillar portion, wherein the pillar portion comprises a tapered pillar foot;
• forming a selector material on the connecting material;
• forming an electrode material on the selector material;
• and
• performing a second patterning process to pattern the memory material stack, the connecting material, the selector material and the electrode material to respectively form a memory element, a connecting structure having the base portion and the pillar portion, a selector and a top electrode, wherein the connecting structure is electrically connecting the memory element to the selector.