Nitrous oxide plays a critical role in semiconductor manufacturing, primarily as an oxidant source in chemical vapor deposition (CVD) processes for silicon dioxide and silicon nitride gate dielectrics.
Silicon Dioxide Growth
In thermal CVD processes, N₂O serves as an oxygen source at temperatures of 750–900°C, reacting with silane (SiH₄) to produce high-quality SiO₂ films:
SiH₄ + 2N₂O → SiO₂ + 2N₂ + 2H₂
The advantage over pure oxygen processes is better film uniformity and controllable growth rates at lower temperatures, which is critical for advanced node manufacturing.
Typical Deposition Temperature
750 – 900°C
Gate Dielectric Applications
N₂O annealing of thin silicon dioxide films (2–5 nm) at 800–1000°C introduces nitrogen at the SiO₂/Si interface, reducing interface trap density and improving device reliability in CMOS transistors.