Specific Process Knowledge/Thin film deposition/Deposition of Gold/Adhesion layers: Difference between revisions
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The film started to dewet between 100°C and 200°C. When Ti was used as adhesion layer, the nanostructure of Au at room temperature had a smaller grain size and complete [111] orientation. When the sample was treated with the same annealing conditions as pure Au, the effect of the temperature on the nanostructure was very different: the annealing did not affect the continuity of the film up to 500°C and up to 200°C there was little grain growth. From 400°C the grain size started to increase, but not at the levels of pure Au. For the Cr/Au bilayer system, the Au film had a slightly smaller average grain size than in the Ti/Au case. Due to the low average grain size, a lot of grains were not properly indexed and are displayed as black areas. The Au layer maintained a continuous morphology up to 500°C also in this case, but the increase of the grain size was more limited than in the Ti/Au sample. | The film started to dewet between 100°C and 200°C. When Ti was used as adhesion layer, the nanostructure of Au at room temperature had a smaller grain size and complete [111] orientation. When the sample was treated with the same annealing conditions as pure Au, the effect of the temperature on the nanostructure was very different: the annealing did not affect the continuity of the film up to 500°C and up to 200°C there was little grain growth. From 400°C the grain size started to increase, but not at the levels of pure Au. For the Cr/Au bilayer system, the Au film had a slightly smaller average grain size than in the Ti/Au case. Due to the low average grain size, a lot of grains were not properly indexed and are displayed as black areas. The Au layer maintained a continuous morphology up to 500°C also in this case, but the increase of the grain size was more limited than in the Ti/Au sample. | ||
[[File:PictureA.png| | [[File:PictureA.png|350px|center|thumb|Fig. 3: IPFZ maps showing the nanostructure evolution with temperature of a 20 nm pure Au film (left column), a 2nm Ti/20 nm Au bilayer (center column) and a 2nm Cr/20 nm Au bilayer system (right column).]] | ||
A more quantitative analysis of the grain size increase for all three samples was performed between the map at room temperature and the one after the annealing at 200°C, since at such temperature the nanostructure of Au was still continuous and the dewetting was not affecting the analysis significantly. The results are reported in Fig. 16. The average grain size of the pure Au sample increased from 97 nm to 105 nm in the evaluated temperature range (Fig. 16a), the one of the Ti/Au sample from 45 nm to 56 nm (Fig. 16b) and the one of the Cr/Au sample almost did not change, increasing from 34 nm to 36 nm (Fig. 16c). At higher temperatures, the Au grain size increase was very different between the two adhesion layers. Figure 17a shows the variation for Ti/Au between room temperature and 500°C: the plotted average grain size value increased from 45 nm to 113 nm after the annealing. Figure 17b shows the variation for Cr/Au: in this case the grain size increase is lower, varying from 34 nm to 44 nm, highlighting the higher nanostructure stability guaranteed by Cr respect to Ti. | A more quantitative analysis of the grain size increase for all three samples was performed between the map at room temperature and the one after the annealing at 200°C, since at such temperature the nanostructure of Au was still continuous and the dewetting was not affecting the analysis significantly. The results are reported in Fig. 16. The average grain size of the pure Au sample increased from 97 nm to 105 nm in the evaluated temperature range (Fig. 16a), the one of the Ti/Au sample from 45 nm to 56 nm (Fig. 16b) and the one of the Cr/Au sample almost did not change, increasing from 34 nm to 36 nm (Fig. 16c). At higher temperatures, the Au grain size increase was very different between the two adhesion layers. Figure 17a shows the variation for Ti/Au between room temperature and 500°C: the plotted average grain size value increased from 45 nm to 113 nm after the annealing. Figure 17b shows the variation for Cr/Au: in this case the grain size increase is lower, varying from 34 nm to 44 nm, highlighting the higher nanostructure stability guaranteed by Cr respect to Ti. | ||