The age of silicon is coming to an end as we approach its limitations in an effort to maintain Moore's law. Finding its replacement is not easy though, but there are many promising candidates for building transistors in the teens of nanometers. Among them is indium gallium arsenide which researchers at MIT have recently made a 22 nm transistor with.
Indium gallium arsenide is a compound semiconductor already used in fiber-optic communication and radar technologies, where there is a greater allowance for large components, unlike within CPUs and other microchips. This means that part of the effort to make the indium gallium arsenide transistors was to properly adapt the current techniques for manufacturing silicon components to the different material. These techniques include deposition methods to build up the transistors and etching to properly shape and move the components. If this compound semiconductor is to be the replacement for silicon though, current fabrication technologies will need to be redeveloped for the new material.
Ultimately the researchers want to take this technology to sub-10 nm sizes, but before that they are focusing on increasing the speed of the transistors. After all, you do not want to increase the count of slow transistors.