Wafer testing is a step performed during semiconductor device fabrication. It is the basis for modern nanoelectronic semiconductor device fabrication. They function as an ohmic electrical contact in the middle of a semiconductor device. Since then, Samsung has been a leader in semiconductor device fabrication. Often the package forms one contact for the semiconductor device. Photolithography is one of these methods, often applied to semiconductor device fabrication. Commercial nanoelectronic semiconductor device fabrication began in the 2010s. Surface passivation refers to a common semiconductor device fabrication process critical to modern electronics. This is often considered the first patent on a semiconductor device. Atalla and Kahng developed both the PMOS and NMOS processes for MOSFET semiconductor device fabrication. STI is created early during the semiconductor device fabrication process, before transistors are formed. High purity oxygen, nitrogen, and argon, used for semiconductor device fabrication, require cryogenic distillation. After the war, Shockley decided to attempt the building of a triode-like semiconductor device. The conductive shunt therefore does not compromise integrity and reliability of the semiconductor device. After the war, William Shockley decided to attempt the building of a triode-like semiconductor device.