Things actually broke at 90nm. Gate leakage went up enough that most analog/RF circuits scaled their transistors back up to 130-150nm dimensions while the digital guys cashed in the density increase one last time.
65nm was the first node where static RAM cells didn't scale with the rest of the digital circuitry. RAM cells are more sensitive to leakage since they have a "writability constraint" where you have to be able to shove enough electrons from outside the cell, through a transistor, with enough oomph to change the state inside the RAM cell.
40nm was where RAM scaling really broke. Designers had to start jumping through amazing hoops to support tricks for the manufacturing guys to eke out the last jump even for standard digital circuits. Most technologies started trading off multiple gate oxide thicknesses to manage leakage current.
28nm was where everything basically went to hell. The strong form of Moore's Law (twice the transistors for same cost) broke. RAM cells are way off the scaling curve. Leakage is everywhere. Multiple gate oxide thicknesses are the rule, not the exception. Designers are jumping through tremendous hoops for manufacturing (aligning all gates in the same direction over the entire chip, for example).
Below 28nm has been a disaster, and, as pointed out, a lot of the sub-28nm stuff is more marketing than actual physical dimensions.
Things actually broke at 90nm. Gate leakage went up enough that most analog/RF circuits scaled their transistors back up to 130-150nm dimensions while the digital guys cashed in the density increase one last time.
65nm was the first node where static RAM cells didn't scale with the rest of the digital circuitry. RAM cells are more sensitive to leakage since they have a "writability constraint" where you have to be able to shove enough electrons from outside the cell, through a transistor, with enough oomph to change the state inside the RAM cell.
40nm was where RAM scaling really broke. Designers had to start jumping through amazing hoops to support tricks for the manufacturing guys to eke out the last jump even for standard digital circuits. Most technologies started trading off multiple gate oxide thicknesses to manage leakage current.
28nm was where everything basically went to hell. The strong form of Moore's Law (twice the transistors for same cost) broke. RAM cells are way off the scaling curve. Leakage is everywhere. Multiple gate oxide thicknesses are the rule, not the exception. Designers are jumping through tremendous hoops for manufacturing (aligning all gates in the same direction over the entire chip, for example).
Below 28nm has been a disaster, and, as pointed out, a lot of the sub-28nm stuff is more marketing than actual physical dimensions.