| CPC H10B 43/40 (2023.02) [H01L 21/02164 (2013.01); H01L 21/0217 (2013.01); H01L 21/02532 (2013.01); H01L 21/02592 (2013.01); H01L 21/2251 (2013.01); H01L 21/31111 (2013.01); H01L 21/32053 (2013.01); H01L 23/528 (2013.01); H01L 29/458 (2013.01); H01L 29/665 (2013.01); H01L 29/66742 (2013.01); H01L 29/78642 (2013.01); H10B 43/10 (2023.02); H10B 43/27 (2023.02)] | 16 Claims |

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1. A memory circuit formed on a semiconductor substrate having a planar surface, the semiconductor substrate having formed therein circuitry for memory operations, the memory circuit comprising:
an array of memory strings, wherein each memory string comprises a plurality of memory transistors and a common source or drain region coupled to each memory transistor of the memory string;
an interconnect layer formed above and parallel the planar surface of the semiconductor substrate, the interconnect layer having a plurality of conductors each being electrically connected to a portion of the circuitry for memory operations; and
one or more select transistors each formed above, alongside or below the array of memory strings, but above the planar surface of the semiconductor substrate, wherein each select transistor (i) is electrically connected between one of the conductors in the interconnect layer and the common source or drain region of a corresponding memory string, (ii) comprises a channel region, a drain region, a source region and a gate electrode, wherein the drain region, the source region and the gate electrode are each formed out of a conductive material, and (iii) electrically connects, when rendered conducting, one of the conductors in the interconnect layer to the common source or drain region of a corresponding memory string.
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