A first memory level includes a first plurality of memory cells that
includes every memory cell in the first memory level. Each memory cell
includes a vertically oriented p-i-n diode in the form of a pillar that
includes a bottom heavily doped p-type region, a middle intrinsic or
lightly doped region, and a top heavily doped n-type region. The first
plurality of memory cells includes programmed cells and unprogrammed
cells, wherein programmed cells comprise at least half of the first
plurality of memory cells. Current flowing through the p-i-n diodes of at
least 99 percent of the programmed cells when a voltage between about 1.5
volts and about 3.0 volts is applied between the bottom heavily doped
p-type region and the top heavily doped n-type region is at least 1.5
microamps.