Integration of epitaxially grown channel selector with MRAM device
A magnetic memory array having an epitaxially grown vertical semiconductor selector connected with a memory element via a bottom electrode such as TaN. An electrically conductive contact such as tungsten (W) or TaN can be included between the vertical semiconductor channel and the TaN bottom electrode. The electrically conductive contact and the TaN bottom electrode can both be formed by a damascene process wherein an opening is formed in an oxide layer and a metal is deposited into the opening. A chemical mechanical polishing process can then be performed to remove portions of the metal that extend out of the opening in the oxide layer over the oxide surface.
1. A memory device comprising:
a selector comprising an epitaxial semiconductor column having a side surrounded by gate dielectric;
an electrically conductive gate line located such that the gate dielectric separates the epitaxial semiconductor column from the electrically conductive gate line;
a memory element; and
an electrically conductive bottom electrode located between and electrically connecting the memory element with the epitaxial semiconductor column.
2. The memory device as in claim 1 , wherein the bottom electrode has a width that is larger than a width of the memory element.
3. The memory device as in claim 1 , wherein the bottom electrode has a smooth surface that contacts the memory element.
4. The memory device as in claim 1 , wherein the bottom electrode contacts both the memory element and an end of the epitaxial semiconductor column.
5. The memory device as in claim 1 , further comprising an electrically conductive contact located between the bottom electrode and the epitaxial semiconductor column.
6. The memory device as in claim 5 , wherein the electrically conductive contact comprises one or more of W and TaN.
7. The memory device as in claim 1 , wherein the bottom electrode has a width that is self-aligned with the epitaxial semiconductor column, and wherein the gate dielectric layer extends to surround a side of the bottom electrode.
8. The memory device as in claim 1 , wherein the memory element is a perpendicular magnetic tunnel junction element.
9. The memory device as in claim 1 , wherein the epitaxial semiconductor column comprises one or more of Si, SiGe, GaAs and GaA compounds.
10. The memory device as in claim 1 , wherein the epitaxial semiconductor column comprises Si.
11. The memory device as in claim 1 , wherein memory element is a tunnel junction element or a phase change element.
12. The memory element as in claim 1 , wherein the bottom electrode comprises TaN.