Memory devices and methods of manufacturing thereof

A method for fabricating a memory device, comprising:

• forming a first stack over a substrate, the first stack comprising a first nanosheet, a second nanosheet over the first nanosheet, and a third nanosheet over the second nanosheet;
• forming a second stack over the substrate, the second stack comprising a fourth nanosheet, a fifth nanosheet over the fourth nanosheet, and a sixth nanosheet over the fifth nanosheet, wherein the first nanosheet, the second nanosheet, the third nanosheet, the fourth nanosheet, the fifth nanosheet, and the sixth nanosheet extend along a first direction;
• removing respective end portions of the fourth nanosheet and the sixth nanosheet wherein the first stack is covered by a blocking mask during removal of the respective end portions of the fourth nanosheet and the sixth nanosheet;
• forming a plurality of spacers at respective etched end portions of the fourth nanosheet and the sixth nanosheet wherein the first stack is covered by the blocking mask during formation of the plurality of spacers;
• forming a first source/drain feature in physical contact with respective first side surfaces of the first nanosheet, the second nanosheet, and the third nanosheet;
• and
• forming a second source/drain feature adjacent to the first stack and the second stack and physically contacting respective second side surfaces of the first nanosheet, the second nanosheet, and the third nanosheet, and a first side surface of the fifth nanosheet, wherein the respective second side surfaces of the first nanosheet, the second nanosheet, and the third nanosheet are perpendicular to the first direction.

A method for fabricating a memory device, comprising:

• forming a first stack over a substrate, the first stack comprising a first nanosheet, a second nanosheet over the first nanosheet, and a third nanosheet over the second nanosheet;
• forming a second stack over the substrate, the second stack comprising a fourth nanosheet, a fifth nanosheet over the fourth nanosheet, and a sixth nanosheet over the fifth nanosheet, wherein the first nanosheet, the second nanosheet, the third nanosheet, the fourth nanosheet, the fifth nanosheet, and the sixth nanosheet extend along a first direction;
• removing respective end portions of the fourth nanosheet and the sixth nanosheet wherein the first stack is covered by a blocking mask during removal of the respective end portions of the fourth nanosheet and the sixth nanosheet;
• forming a plurality of spacers at respective etched end portions of the fourth nanosheet and the sixth nanosheet wherein the first stack is covered by the blocking mask during formation of the plurality of spacers;
• forming a first source/drain feature in physical contact with respective first side surfaces of the first nanosheet, the second nanosheet, and the third nanosheet;
• forming a second source/drain feature adjacent to the first stack and the second stack and physically contacting respective second side surfaces of the first nanosheet, the second nanosheet, and the third nanosheet, and a first side surface of the fifth nanosheet;
• and
• forming a third source/drain feature in physical contact with a second side surface of the fifth nanosheet, wherein the second side surface of the fifth nanostructure is perpendicular to the first direction.