Description:
<jats:p>
The optical properties of dc magnetron-sputtered amorphous Si (a-Si) films grown under different Ar pressures (1.5≤<jats:italic>P</jats:italic>
<jats:sub>Ar</jats:sub>≤12 mTorr) and substrate-target distances (5≤<jats:italic>l</jats:italic>
<jats:sub>s-t</jats:sub>≤30 cm) were investigated. The reflectivity was found to decrease with increasing <jats:italic>P</jats:italic>
<jats:sub>Ar</jats:sub> and <jats:italic>l</jats:italic>
<jats:sub>s-t</jats:sub>, or equivalently with decreasing film density, and was 0.22 at λ=436 nm for the film with the lowest density. The absorption coefficient for this lowest reflectivity film was larger than 1×10<jats:sup>5</jats:sup> cm<jats:sup>-1</jats:sup> at λ=436 nm. These optical properties meet the requirements for anti-reflective coatings in photolithography. Low-reflectivity a-Si could be obtained under deposition conditions for which <jats:italic>P</jats:italic>
<jats:sub>Ar</jats:sub>·<jats:italic>l</jats:italic>
<jats:sub>s-t</jats:sub> was larger than 150 mTorr·cm. The low density and low reflectivity were found to be due to a self-shadowing effect and thermalization of sputtered Si atoms.
</jats:p>