transistortåken

Transistortåken, literally "transistor fog" in Norwegian, is a phenomenon that describes the gradual degradation of performance and reliability in transistors over time due to various physical mechanisms. This term is not a formally recognized scientific or engineering term but is sometimes used colloquially within specific communities to encompass a range of aging effects that collectively reduce the effectiveness of a transistor.

The primary contributors to transistortåken include hot carrier injection, bias-temperature instability, and electromigration. Hot carrier injection occurs when high-energy electrons or holes gain enough energy to overcome the potential barriers within the transistor, leading to charge trapping in the gate oxide. This trapping alters the transistor's threshold voltage and reduces its drive current. Bias-temperature instability is another mechanism where prolonged exposure to electrical stress and elevated temperatures causes changes in the interface between the semiconductor and the gate dielectric, again affecting electrical characteristics. Electromigration, particularly relevant in the interconnects connected to transistors, involves the physical movement of metal atoms under the influence of an electrical current, which can lead to open circuits or increased resistance.

These aging effects can manifest as a gradual increase in leakage currents, a decrease in switching speed, and an overall reduction in the transistor's ability to function correctly. While modern semiconductor manufacturing employs sophisticated design techniques and materials to mitigate these issues, they remain a fundamental consideration in the long-term reliability and lifespan of electronic devices, especially those operating under demanding conditions. The cumulative effect of these degradations can be seen as a "fog" obscuring the transistor's initial performance.