Memory devices which include memory arrays
View Patent ↗Some embodiments include a memory device. The device has a fin with a first source/drain region, a second source/drain region and a channel region. The first source/drain region extends to a first height. The second source/drain region extends to a second height less than the first height. The channel region extends along a trough between the first and second source/drain regions. A charge-storage device is over the first source/drain region. A first sense/access line is along a sidewall of the fin and is spaced from the channel region by dielectric material. A second sense/access line is over the second source/drain region. An uppermost surface of the second sense/access line is beneath an uppermost surface of the first source/drain region. Some embodiments include memory arrays, and some embodiments include methods of forming memory arrays.
1. A memory device comprising a memory array, wherein the memory array comprises:
access transistors arranged in rows and columns; each access transistor having a first source/drain region, a second source/drain region and a channel region between the first source/drain region and the second source/drain region; the access transistors having gates spaced from the channel regions by gate dielectric material, the gate dielectric material comprising silicon dioxide;
capacitors over the first source/drain regions and electrically coupled with the first source/drain regions;
digit lines over the second source/drain regions and electrically coupled with the second source/drain regions; uppermost surfaces of the digit lines being beneath uppermost surfaces of the first source/drain regions; the digit lines extending along the columns;
the capacitors being above the digit lines; the only insulative material vertically between the capacitors and the underlying digit lines being silicon dioxide which merges with the silicon dioxide of the gate dielectric material; and
wordlines extending along the rows and comprising the gates of the access transistors.
2. The memory device of claim 1 wherein the access transistors comprise fins; the fins comprising the first source/drain regions, the second source/drain regions and the channel regions; the channel regions extending along troughs between the first source/drain regions and the second source/drain regions; the gates being along sidewalls of the fins.
3. The memory device of claim 1 wherein the digit lines comprise, in ascending order from the second source/drain regions:
conductively-doped silicon,
titanium silicide,
titanium, and
titanium nitride.
4. The memory device of claim 1 wherein the digit lines comprise titanium-containing material over conductively-doped silicon.
5. The memory device of claim 1 wherein the digit lines comprise metal-containing material over conductively-doped semiconductor material.
6. The memory device of claim 5 wherein the metal-containing material includes one or more of titanium, tungsten, cobalt, nickel and platinum.
7. The memory device of claim 1 wherein the digit lines comprise metal and extend to a region peripheral to the memory array.
8. The memory device of claim 7 wherein the digit lines extend to sense amplifier circuitry within the region peripheral to the memory array.