Semiconductor memory devices with different doping types

A memory device, comprising:

• a plurality of memory cells, wherein each of the memory cells has a first transistor and a second transistor coupled to the first transistor in series;
• a programming word line operatively coupled to a respective gate of each of the first transistors;
• and
• a reading word line operatively coupled to a respective gate of each of the second transistors, wherein:
• each of the first transistors has a first drain/source terminal and a second drain/source terminal and each of the second transistors has a third drain/source terminal and the second drain/source terminal,
• the first drain/source terminals each include a p-type dopant, and
• the second drain/source terminals and the third drain/source terminals each include an n- type dopant.

A method of forming a memory device, comprising:

• forming a stack of alternating first nanosheets and second nanosheets over a substrate;
• defining a first active region and a second active region in the stack;
• forming a dummy gate stack over each of the first active region and the second active region;
• defining a first conduction channel in the first active region and a second conduction channel in the second active region;
• forming a first drain/source structure adjacent the first conduction channel, a second drain/source structure between the first conduction channel and the second conduction channel, and a third drain/source structure adjacent the second conduction channel, wherein forming the first drain/source structure, the second drain/source structure, and the third drain/source structure includes:
• doping the first drain/source structure with a first dopant, and
• doping the second drain/source structure and the third drain/source structure with a second dopant, the first dopant and the second dopant having different conductivity types;
• and
• forming a gate structure in place of the dummy gate stack and the first nanosheets in each of the first conduction channel and the second conduction channel.