Arrays of memory cells are described along with devices thereof and method for manufacturing. Memory cells described herein include self-aligned side wall memory members comprising an active programmable resistive material. In preferred embodiments the area of the memory cell is 4F2, F being the feature size for a lithographic process used to manufacture the memory cell, and more preferably F being equal to a minimum feature size. Arrays of memory cells described herein include memory cells arranged in a cross point array, the array having a plurality of word lines and source lines arranged in parallel in a first direction and having a plurality of bit lines arranged in parallel in a second direction perpendicular to the first direction.