Moore’s Law, first stated in about 1965, stated that the number of transistors on an mass market silicon chip doubles every two years or so. The number of transistors on a chip is a measure of its storage capacity or processing power. The Law was first put forward by Graham Moore, a co founder of Intel.
The limitation which exists is that there is a lower limit to the size of transistor, namely the size of an atom. This limit may in fact be irrelevant if light or quantum computers have become a reality. Many light photons and quatum bits which serve as the storage units can fit inside the same space.