Impact of surface pre-treatment on Pt-nanodot formation induced by remote H2-plasma exposure

Abstract

We evaluated the influence of the surface modification of ultrathin Pt films with remote plasma treatment using pure N2 or pure NH3 on the formation of Pt nanodots (NDs), which was induced by exposing Pt films on ultrathin SiO2 layers to remote H2 plasma. Well-defined Pt NDs were formed from pre-treated Pt films and, at a remote H2 plasma exposure time of 5 min, areal dot density was increased by factors of ∼2.3 for the remote NH3 plasma pre-treatment (5 min) and ∼3.5 for the N2 plasma pre-treatment (3 min), while the areal density of Pt NDs formed by remote H2 plasma for 5 min without the pre-treatment was 1.5 × 1011 cm-2. The results can be interpreted in terms of the surface migration length of Pt atoms being effectively reduced due to the chemisorption of N atoms on the Pt film surface. In addition, we also demonstrated the formation of high-density Pt NDs with an areal density as high as ∼9.0 × 1011 cm-2 by exposing the Pt film pre-treated with SiH4 to the remote H2 plasma.