Magnetoresistive random access memory
A semiconductor device includes a magnetic tunneling junction (MTJ) on a substrate, a first spacer on a first sidewall of the MTJ, and a second spacer on a second sidewall of the MTJ. Preferably, the first spacer and the second spacer are asymmetric, the first spacer and the second spacer have different heights, and a top surface of the MTJ includes a reverse V-shape.
1. A semiconductor device, comprising:
a magnetic tunneling junction (MTJ) on a substrate, wherein a top surface of the MTJ comprises a reverse V-shape, the reverse V-shape comprises a first inclined surface and a second inclined surface, and the MTJ comprises:
a bottom electrode on the substrate;
a free layer on the bottom electrode; and
a top electrode on the free layer;
a first spacer on and directly contacting a first sidewall of the bottom electrode, the free layer, and the top electrode;
a second spacer on and directly contacting a second sidewall of the bottom electrode, the free layer, and the top electrode, wherein the first spacer and the second spacer are asymmetric and a top surface of the second spacer is lower than a top surface of the first spacer; and
a first metal interconnection on the MTJ, wherein the first metal interconnection directly contacts only part of the first inclined surface and all of the second inclined surface.
2. The semiconductor device of claim 1 , further comprising:
a first inter-metal dielectric (IMD) layer on the substrate; and
a second metal interconnection under the MTJ and in the first IMD layer.
3. The semiconductor device of claim 2 , further comprising a second IMD layer on the first IMD layer and around the MTJ.
4. The semiconductor device of claim 3 , further comprising the first metal interconnection on the MTJ and the second IMD layer, wherein the first metal interconnection comprises a protrusion contacting a sidewall of the top electrode.
5. The semiconductor device of claim 4 , wherein the protrusion contacts the top electrode, the second spacer, and the second IMD layer directly.
6. The semiconductor device of claim 4 , wherein a bottom surface of the protrusion is higher than a top surface of the free layer.
7. The semiconductor device of claim 3 , further comprising the first metal interconnection on the MTJ and the second IMD layer, wherein the first metal interconnection comprise a first protrusion and a second protrusion.
8. The semiconductor device of claim 7 , wherein the first protrusion contacts a sidewall of the top electrode and the second protrusion contacts another sidewall of the top electrode.
9. The semiconductor device of claim 7 , wherein bottom surfaces of the first protrusion and the second protrusion are higher than a top surface of the free layer.
10. The semiconductor device of claim 1 , wherein the first spacer and the second spacer comprise different heights.