Under Moore's Law, there has been an exponential growth pattern by which chipmakers have been able to double the amount of transistors on chips every 2 years. This has led to faster and cheaper computers. Now scientists say this law has limits.
Intel researchers predict that Moore's Law will only function for two more decades. So far companies have managed to shrink transistor size but now they have had to look for other methods which focus more on design. The biggest barrier is physics.
The barrier researchers see is that with gates below 5 nanometers (1 nanometer=1 billionth of 1 meter), electrons start to tunnel and their activity becomes more difficult to control. By 2018 or 2019, scientists say 5 nanometer chips will debut. Source