Vertical thyristor memory with minority carrier lifetime reduction
Apparatus and methods for reducing minority carriers in a memory array are described herein. Minority carriers diffuse between ON cells and OFF cells, causing disturbances during write operation as well as reducing the retention lifetime of the cells. Minority Carrier Lifetime Killer (MCLK) region architectures are described for vertical thyristor memory arrays with insulation trenches. These MCLK regions encourage recombination of minority carriers. In particular, MCLK regions formed by conductors embedded along the cathode line of a thyristor array, as well as dopant MCLK regions are described, as well as methods for manufacturing thyristor memory cells with MCLK regions.
1. A cross-point memory array including silicon thyristors interconnected by anode lines and cathode lines in a cross-point arrangement, the array comprising:
a first silicon thyristor comprising a first cathode;
a second silicon thyristor comprising a second cathode;
a trench formed between the first silicon thyristor and the second silicon thyristor; and
a conductor material region formed in the trench and located along a minority carrier diffusion pathway between the first silicon thyristor and the second silicon thyristor, wherein the conductor material region connects the first cathode of the first silicon thyristor and the second cathode of the second silicon thyristor forming a cathode line in the cross-point memory array.
2. The cross-point memory array of claim 1 , wherein the conductor material region contacts a surface of the first cathode without extending into the first cathode and contacts a surface of the second cathode without extending into the second cathode.
3. The cross-point memory array of claim 1 , wherein the conductor material region is electrically coupled to the first cathode through a first metal silicide region, and is electrically coupled to the second cathode through a second metal silicide region.
4. The cross-point memory array of claim 1 , wherein the conductor material region is separated from a base of the trench by a layer of insulating material.
5. The cross-point memory array of claim 1 , wherein the conductor material region is formed by a chemical vapor deposition process.
6. The cross-point memory array of claim 5 , wherein the conductor material region comprises Tungsten.