IBM has been mostly irrelevant to semiconductor process technology for at least a decade. I doubt many outside IBM can clear state why they even still do it. They certainly don't make any money from it. Yerning for the glory days perhaps?
That is the length of the whole unit cell. There are more atoms within the cell since it is a diamond crystal structure. Actual figures depend on orientation but for a 100 direction it would be 4x that.
Patterning at 7nm is obviously tough but sounds people think it can be done...but is Mosfet still working at 7nm?...what is Ion/Ioff ratio?...how many dopant atoms are within transistor volume? what about statistical variations that could be huge?