A memory device comprises a reference conductor, and a stack of conductive strips separated by insulating strips, where the conductive strips in the stack extend in a first direction, and the stack is disposed on the reference conductor. The memory device comprises a plurality of hemi-cylindrical vertical channel structures extending through respective vias in the conductive strips in the stack, and comprising semiconductor films in electrical contact with the reference conductor having outside surfaces. Each of the hemi-cylindrical vertical channel structures has a divided elliptical cross section with a major axis tilted relative to the first direction. The memory device comprises data storage structures between the outside surfaces of the semiconductor films and sidewalls of the vias in the conductive strips.