Magnetic memory device with a common source having an array of openings, system, and method of fabrication
Memory devices include an array of memory cells including magnetic tunnel junction regions. The array of memory cells includes access lines extending in a first direction and data lines extending in a second direction transverse to the first direction. A common source electrically couples memory cells of the array in both the first direction and the second direction. Electronic systems include such a memory device electrically coupled to a processor, to which at least one input device and at least one output device is electrically coupled. Methods of forming such an array of memory cells including a common source.
1. A memory device, comprising:
memory cells comprising:
magnetic tunnel junction regions;
access devices; and
cell contacts vertically extending between and electrically coupling the magnetic tunnel junction regions and the access devices;
access lines electrically coupled to the access devices and extending in a first direction;
data lines electrically coupled to the magnetic tunnel junction regions and extending in a second direction perpendicular to the first direction;
a common source configured to be selectively electrically coupled to all of the memory cells and exhibiting an array of openings therein through which the cell contacts of the memory cells vertically extend; and
source contacts electrically coupled to the common source and the access devices and intervening between all adjacent openings of the array of openings in the common source along the first direction and the second direction.
2. The memory device of claim 1 , wherein each of the magnetic tunnel junction regions comprise:
a fixed magnetic region;
a free magnetic region; and
a non-magnetic region between the fixed magnetic region and the free magnetic region.
3. The memory device of claim 2 , wherein the fixed magnetic region and the free magnetic region have magnetic orientations perpendicular to a base semiconductor structure over which the magnetic tunnel junction regions are formed.
4. The memory device of claim 1 , wherein the memory cells are staggered, such that a first row of aligned memory cells are offset from a second row of aligned memory cells immediately adjacent to the first row.
5. The memory device of claim 1 , wherein the common source comprises tungsten material.
6. The memory device of claim 1 , wherein the access devices comprise dual-channel access devices.
7. The memory device of claim 6 , wherein the dual-channel access devices each comprise two semiconductor source regions and a single semiconductor drain region.
8. The memory device of claim 7 , wherein the common source is electrically coupled to the two semiconductor source regions of each of the dual-channel access devices.
9. The memory device of claim 1 , wherein the array of openings in the common source comprises:
columns of openings extending in the first direction, each opening of each column of openings separated from each other opening of the column of openings adjacent thereto by one of the source contacts; and
rows of openings extending in the second direction, each opening of each row of openings separated from each other opening of the row of openings adjacent thereto by one of the source contacts.
10. The memory device of claim 9 , wherein the source contacts are arranged in an array comprising columns of the source contacts extending in the first direction and rows of the source contacts extending in the second direction, each of the source contacts substantially evenly spaced apart from each other of the source contacts adjacent thereto.
11. The memory device of claim 1 , wherein each of the source contacts is substantially equidistant from each opening of the array of openings adjacent thereto.
12. An electronic system, comprising:
a processor;
an input device and an output device electrically coupled to the processor; and
a memory device electrically coupled to the processor, the memory device comprising:
memory cells comprising:
magnetic tunnel junction regions;
dual-channel access devices; and
conductive cell contacts electrically coupling the magnetic tunnel junction regions and the dual-channel access devices;
conductive access lines extending in a first direction and electrically coupled to the dual-channel access devices of the memory cells;
conductive data lines extending in a second direction perpendicular to the first direction and electrically coupled to the magnetic tunnel junction regions of the memory cells;
a common source electrically coupled to all of the dual-channel access devices of the memory cells and exhibiting openings therein through which the conductive cell contacts of the memory cells vertically extend; and
source contacts electrically coupled to the common source and the access devices, the source contacts intervening between each adjacent pair of the openings in the common source along the first direction and the second direction.
13. The electronic system of claim 12 , wherein the common source comprises:
first linear portions extending in a third direction between about 35 degrees and about 55 degrees offset from the second direction; and
second linear portions extending in a fourth direction perpendicular to the third direction and intersecting the first linear portions over each of the source contacts.
14. The electronic system of claim 12 , wherein the dual-channel access devices each comprise a single drain region electrically coupled to one of the conductive cell contacts and two source regions electrically coupled to the common source.
15. The electronic system of claim 12 , wherein a maximum resistance across the common source is about 20Ω or less.
16. The electronic system of claim 12 , wherein the conductive access lines are positioned in trenches formed in a base semiconductor structure.
17. The electronic system of claim 12 , wherein the common source is electrically coupled to semiconductor source regions of the dual-channel access devices of the memory cells.
18. A method of forming an array of memory cells, comprising:
forming access devices having access lines extending in a first direction;
forming cell contacts coupled to the access devices;
forming magnetic tunnel junction regions over the cell contacts;
forming data lines over the magnetic tunnel junction regions, the data lines extending in a second direction perpendicular to the first direction;
forming a common source coupled to source contacts of adjacent memory cells in both the first direction and the second direction, the common source exhibiting an array of openings therein through which the cell contacts vertically extend; and
forming source contacts electrically coupled to the common source and the access devices, the source contacts intervening between and substantially equally spaced apart from all adjacent openings of the array of openings in the common source along the first direction and the second direction.
19. The method of claim 18 , wherein the common source is formed prior to forming the cell contacts.
20. The method of claim 18 , wherein forming the access devices comprises:
forming trenches in a base semiconductor structure; and
filling the trenches with at least one conductive material to form the access lines.