An arrow 1255 in FIG. 12C shows that the current may generally follow a curved path (e.g., a concave curve) as it flows from source/drain 1240 to source/drain 1242 when transistor 1200 is activated. For example, the current flow may have a downward trajectory in semiconductor fin 1210₂ and an upward trajectory in semiconductor fin 1210₃, e.g., a vertical downward component in semiconductor fin 1210₂ and a vertical upward component in semiconductor fin 1210₃. For example a channel (e.g., a concave channel) may be formed in semiconductor fins 1210₂ and 1210₃ on either side of control gate 1235 and dielectric 1230 and in the portion of semiconductor 1212 that is below (e.g., vertically below) control gate 1235 and dielectric 1230, when transistor 1200 is activated. For example, the channel may be concave relative to (e.g., when viewed from) the uppermost surfaces semiconductor fins 1210₂ and 1210₃.

Positioning the source/drains 1240 and 1242 of transistor 1200 so that their upper (e.g., uppermost) surfaces are above uppermost ends of dielectric (e.g., gate dielectric) 1230 of transistor 1200 allows the distance D3 (FIG. 12C) in the x-direction between source/drains 1240 and 1242 to be less than the distance D2 in the x-direction between the source/drains 115 and 117 of a finFET 100 (FIG. 4). The decreased distance allows for more transistors 1200 in the x-direction, e.g., under a stacked memory array to accommodate for more memory cells in a stack of memory cells.