Phase change memory apparatuses
Phase change memory apparatuses include memory cells including phase change material, bit lines electrically coupled to aligned groups of at least some of the memory cells, and heating elements electrically coupled to the phase change material of the memory cells. The heating elements include vertical portions extending in a bit line direction. Additional phase change memory apparatuses include dummy columns positioned between memory columns and base contact columns. The dummy columns include phase change memory cells and lack heating elements coupled to the phase change memory cells thereof. Additional phase change memory apparatuses include heating elements operably coupled to phase change memory cells. An interfacial area between the heating elements and the phase change memory cells has a length that is independent of a bit line width. Methods relate to forming such phase change memory apparatuses.
1. A phase change memory apparatus, comprising:
an array of vertical memory cells comprising a phase change material;
bit lines electrically coupled to respective aligned groups of at least some of the vertical memory cells of the array, the bit lines including a bit line width in a first horizontal direction and a bit line length in a second horizontal direction transverse to the first horizontal direction; and
heating elements electrically coupled to respective phase change material of individual vertical memory cells of the array, the heating elements comprising respective substantially planar vertical portions having a height in a vertical direction transverse to the first horizontal direction and the second horizontal direction, a width parallel to the second horizontal direction, and a thickness parallel to the first horizontal direction, wherein the thickness of the substantially planar vertical portions of the heating elements parallel to the first horizontal direction is less than the width of the substantially planar vertical portions of the heating elements parallel to the second horizontal direction and the width of the substantially planar vertical portions of the heating elements parallel to the second horizontal direction is less than the bit line width in the first horizontal direction.
2. The apparatus of claim 1 , further comprising bipolar junction transistor selectors in electrical communication with the heating elements, comprising:
n-doped semiconductor base regions including elongated portions parallel to the second horizontal direction; and
p-doped semiconductor emitters between the n-doped semiconductor base regions and respective individual heating elements.
3. The apparatus of claim 2 , wherein the bipolar junction transistor selectors further comprise common p-doped semiconductor collectors located on a side of the n-doped semiconductor base regions opposite the p-doped semiconductor emitters.
4. The apparatus of claim 2 , further comprising base contacts electrically coupled to the n-doped semiconductor base regions.
5. The apparatus of claim 4 , further comprising dummy memory cells immediately adjacent to the base contacts, the dummy memory cells comprising a phase change memory material, wherein no heating elements are in physical contact with the phase change memory material of the dummy memory cells.
6. The apparatus of claim 1 , wherein the bit lines comprise a copper material.
7. The apparatus of claim 1 , wherein the phase change material of the vertical memory cells of the array comprises a chalcogenide material.
8. A phase change memory apparatus, comprising:
an array of vertical memory columns including phase change memory cells, heating elements coupled to the phase change memory cells, conductive adhesion materials coupled to the phase change memory cells on a side of the phase change memory cells opposite the heating elements, and conductive bit lines coupled to the conductive adhesion materials, the conductive bit lines including a bit line width in a first horizontal direction and a bit line length in a second horizontal direction transverse to the first horizontal direction, and substantially planar vertical portions of the heating elements having a height in a vertical direction transverse to the first horizontal direction and the second horizontal direction, a width parallel to the second horizontal direction, and a thickness parallel to the first horizontal direction, wherein the thickness of the substantially planar vertical portions of the heating elements parallel to the first horizontal direction is less than the width of the substantially planar vertical portions of the heating elements parallel to the second horizontal direction and the width of the substantially planar vertical portions of the heating elements parallel to the second horizontal direction is shorter than the bit line width in the first horizontal direction;
bipolar junction transistor (BJT) selectors coupled to the heating elements, the BJT selectors including n-doped semiconductor base regions including elongated portions parallel to the second horizontal direction;
base contact columns coupled to the n-doped semiconductor base regions; and
dummy cell columns positioned between the array of vertical memory columns and the base contact columns, the dummy cell columns including phase change memory material positioned over a dielectric material, the dummy cell columns lacking the heating elements in physical contact with the phase change memory material thereof.
9. The apparatus of claim 8 , wherein the dummy cell columns comprise the conductive adhesion materials coupled to the phase change memory material of the dummy cell columns, the conductive adhesion materials including elongated portions parallel to the second horizontal direction.
10. The apparatus of claim 8 , wherein material of the dummy cell columns further comprises a doped semiconductor region, and wherein the dielectric material of the dummy cell columns comprises one or more dielectric materials located between the phase change memory material and the doped semiconductor region.
11. The apparatus of claim 8 , wherein at least some of the substantially planar vertical portions of the heating elements of the array of vertical memory columns are substantially coplanar with each other.
12. The apparatus of claim 8 , wherein the BJT selectors further comprise p-doped semiconductor emitter regions coupled to the n-doped semiconductor base regions and coupled to respective heating elements of the array of vertical memory columns.
13. The apparatus of claim 8 , wherein the dummy cell columns further comprise doped semiconductor regions coupled to the n-doped semiconductor base regions, and at least some of the doped semiconductor regions are sufficiently n-doped to form an electrical short with respective n-doped semiconductor base regions.
14. A phase change memory apparatus, comprising:
an array of vertical phase change memory cells;
bit lines coupled to the vertical phase change memory cells of the array, the bit lines aligned in a first horizontal direction and including a bit line width parallel to the first horizontal direction and a bit line length parallel to a second horizontal direction transverse to the first horizontal direction;
L-shaped heating elements operably coupled to the vertical phase change memory cells; and
an elongated dielectric structure between a horizontal portion of the heating elements and the vertical phase change memory cells, and vertical portions of the heating elements including a height in a vertical direction transverse to the first horizontal direction and the second horizontal direction, a width parallel to the second horizontal direction, and a thickness parallel to the first horizontal direction, wherein the thickness of the vertical portions of the heating elements parallel to the first horizontal direction is shorter than the width of the vertical portions of the heating elements parallel to the second horizontal direction and the width of the vertical portions of the heating elements parallel to the second horizontal direction is shorter than the bit line width parallel to the first horizontal direction.
15. The apparatus of claim 14 , wherein the second horizontal direction is perpendicular to the first horizontal direction.
16. The apparatus of claim 14 , wherein at least some features of the array of vertical phase change memory cells exhibit a tight pitch.