Process-induced forming of oxide RRAM
Embodiments of present invention provide a method of forming a resistive random-access memory (RRAM). The method includes forming a dielectric layer on top of a supporting structure, wherein the dielectric layer has a bottom electrode embedded therein; forming an oxide layer on top of the bottom electrode; treating the oxide layer in a plasma environment; forming a top electrode on top of the oxide layer; forming a first interlevel-dielectric (ILD) layer on top of the top electrode; forming a via contact and a first metal layer in the first ILD layer, wherein the first metal layer is in contact with the top electrode through the via contact; forming a capping layer on top of the first metal layer through a plasma-enhanced deposition process; and causing formation of one or more filaments in the oxide layer during the plasma-enhanced deposition process. A structure of the RRAM is also provided.
1. A method of forming a semiconductor structure, the method comprising:
forming a dielectric layer on top of a supporting structure, wherein the dielectric layer has a bottom electrode embedded therein;
forming an oxide layer on top of the bottom electrode;
forming a top electrode on top of the oxide layer;
forming an encapsulation layer to cover the oxide layer and the top electrode;
forming a first interlevel-dielectric (ILD) layer on top of the top electrode;
forming a via contact and a first metal layer in the first ILD layer, wherein the first metal layer is in contact with the top electrode through the via contact;
forming a capping layer on top of the first metal layer; and
causing formation of one or more filaments in the oxide layer.
2. The method of claim 1 , wherein the oxide layer is a layer of hafnium-oxide (HfO), tantalum-oxide (TaO), titanium-oxide (TiO), or a combination thereof; the capping layer is formed through a plasma-enhanced-chemical-vapor-deposition (PECVD) process; and the one or more filaments are formed during the PECVD process.
3. The method of claim 2 , further comprising, before forming the top electrode, subjecting the oxide layer to a plasma environment that contains hydrogen, thereby causing the oxide layer to contain hydrogen with a concentration level that is less than 10 20 atoms/cm 3 and to have oxygen vacancies.
4. The method of claim 3 , wherein causing the formation of one or more filaments in the oxide layer comprises funneling free electrons to the oxide layer during the PECVD process and using the oxygen vacancies as precursors in forming the one or more filaments.
5. The method of claim 1 , wherein the capping layer is a layer of carbon-hydrogen containing silicon-nitride that is formed through a plasma-enhanced-chemical-vapor-deposition process.
6. The method of claim 1 , wherein the capping layer is formed in a plasma-enhanced-chemical-vapor-deposition process in an environment that contains precursors of at least silicon, nitrogen, carbon, and hydrogen.
7. The method of claim 1 , wherein the encapsulation layer is a conformal dielectric layer.
8. The method of claim 1 , wherein the via contact is made through the encapsulation layer to be in direct contact with the top electrode.