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DVH Group Laser Ablation Lab

Laser ablation, also known as pulsed laser deposition, is a physical vapor deposition technique in which a pellet of material is hit with an intense UV laser pulse creating a stoichiometrically correct plume in which your substrate sits.  Typically the substrates are heated to about 800 C so that surface diffusion is enhanced making epitaxial growth possible.  Laser ablation can be done in vacuum, but typically most compounds, including the high-Tc cuprates, require the presence of oxygen or other gas. We typically perform ablations at O₂ pressures between 50-500 mTorr depending on what doping level we desire.

      The laser we use is a Lamba-Physik, Compex 301, ArF Excimer laser.  We have two laser ablation chambers.  One is dedicated to High-Tc materials and also includes sputtering guns, and an ion mill so that in-situ processing can be performed after an ablation.  An assortment of lenses and mirrors is used to focus and send the beam to the chosen chamber.  We recently incorporated a computer controlled mirror which can scan the laser beam over the target creating better uniformity and the use of larger substrates.   Shown are pictures of our ablation facility and a schematic diagram of how it works.