Laser anneal for MRAM encapsulation enhancement
A low temperature deposited (400° C. or less) dielectric passivation layer is formed on physically exposed surfaces of a material stack including a multilayered magnetic tunnel junction (MTJ) pillar and a top electrode. A laser anneal is then performed to improve the physical and chemical properties of the low temperature deposited dielectric passivation layer, without negatively impacting the multilayered MTJ pillar.
1. A method of forming a magnetoresistive random access memory (MRAM) device, the method comprising:
forming a structure including a multilayered magnetic tunnel junction (MTJ) pillar located on a surface of a conductive landing pad, and a top electrode located on the multilayered MTJ pillar;
forming a dielectric passivation layer on physically exposed surfaces of the structure utilizing a deposition process that is performed at a temperature of 400° C. or less; and
performing a laser anneal on the structure including the dielectric passivation layer to provide a laser annealed dielectric passivation layer, without negatively impacting the multilayered MTJ pillar.
2. The method of claim 1 , furthering comprising performing an etch, prior to the performing of the laser anneal, to remove the dielectric passivation layer from horizontal surfaces of the structure, while maintaining the dielectric passivation layer on outermost sidewalls of the top electrode and the multilayered MTJ pillar.
3. The method of claim 1 , wherein the dielectric passivation layer is composed of silicon nitride, or a dielectric material containing atoms of carbon and hydrogen.
4. The method of claim 1 , wherein the temperature of the deposition process used in the forming of the dielectric passivation layer is from 200° C. to 400° C.
5. The method of claim 1 , wherein the laser anneal comprises a single laser anneal or multiple laser anneals.
6. The method of claim 1 , wherein the laser anneal is performed for a duration from about 1 nanosecond to about 500 nanoseconds.
7. The method of claim 1 , wherein the dielectric passivation layer has a first hydrogen content and a first nitrogen content, and the laser annealed dielectric passivation layer has a second hydrogen content that is less than the first hydrogen content, and a second nitrogen content that is less than the first nitrogen content.
8. The method of claim 1 , wherein the dielectric passivation layer has a first Young's modulus, and the laser annealed dielectric passivation layer has a second Young's modulus that is greater than the first Young's modulus.
9. The method of claim 1 , wherein an entirety of the laser annealed dielectric passivation layer is modified by the laser anneal.
10. The method of claim 1 , wherein only a surface portion of the laser annealed dielectric passivation layer is modified by the laser anneal.