According to Paul McLellan, summarizing a tutorial by Chenmin Hu,
Planar transistors are at the end of their life because too much silicon is far from the gate and so not turned off by the gate. So make sure no silicon is far from gate. Either build a thin fin and wrap the gate around it, or switch from bulk silicon to a thin film of silicon on an insulator. Hence the future is FinFET and/or FD-SOI and we’ll see how this plays out.
For more on FinFET, see these lessons at SemiWiki.com by “ChipGuy”. (Scroll to bottom.)