Process node
The name given to a generation of chip-making technology. It is expressed as a length, such as 2 nanometers, but no longer corresponds to any actual dimension.
Generations used to be named after a dimension that could really be measured on the chip, such as the length of the transistor gate. From the late 1990s the names and the dimensions drifted apart, and once three-dimensional transistors arrived there was no longer any feature on the chip matching the number. Even in a 2-nanometer transistor the gate is more than ten nanometres long.
The number is closer to a product name meaning more advanced than the last one, and the same number from different companies means different things. In 2020 a group of researchers proposed describing generations by density, such as transistors per unit area, instead of by name[1]. To compare generations, look at measured density, speed and power rather than the label.
Related terms
- Gate-all-aroundA transistor structure in which the channel is a stack of thin sheets (nanosheets), each fully surrounded by the gate on all sides.
- FinFETA three-dimensional transistor in which the channel stands up like a fish's fin and the gate wraps around it on three sides.
- Moore's lawThe rule of thumb that the number of components on a chip keeps doubling at regular intervals. Not a law of physics but a pace the semiconductor industry set itself.