deepultraviolet

Deep ultraviolet (DUV) refers to the portion of the ultraviolet spectrum with wavelengths around 200 to 280 nanometers, with some definitions extending toward 300 nm. The region is characterized by high photon energy and strong absorption in many materials, which influences how it is used and handled.

Because many common materials are opaque in the DUV, optical design relies on specialized substrates and coatings such as calcium fluoride (CaF2), magnesium fluoride (MgF2), and fused silica. Optical components must be carefully engineered to transmit and survive DUV exposure, and air handling is important since absorption and scattering can be significant.

DUV light sources include low-pressure mercury lamps emitting at 254 nm, deuterium lamps for broadband UV output, and excimer lasers such as krypton fluoride (KrF) at 248 nm and argon fluoride (ArF) at 193 nm. In addition, research and development are advancing deep-UV light-emitting diodes (LEDs) and related laser sources, typically based on aluminum gallium nitride (AlGaN), aiming for emission in the 250–280 nm range.

Applications of DUV light span semiconductor manufacturing, where it is used in photolithography to pattern photoresists; disinfection and sterilization, owing to germicidal effects; spectroscopy, materials processing, and surface modification. The region also presents challenges related to short attenuation lengths in air, demanding vacuum or inert environments for many processes, and the scarcity and cost of suitable optics and sources.

The term is used broadly to describe technologies operating in this spectral band; it is distinct from vacuum ultraviolet, which lies below about 200 nm.