Specific Process Knowledge/Thin film deposition/Deposition of Gold/Adhesion layers: Difference between revisions
| Line 17: | Line 17: | ||
From the cross section profile of the 2nm Au sample (Fig. 2a), it is clear that Au, when deposited directly on SiO2, in order to reduce the interface energy, forms a nanoparticle-like layer in contrast to a continuous film. The diameter of the nanoparticles is about 10 nm. The nanoparticle morphology is confirmed by AFM analysis (Fig. 2b). The RMS surface roughness was measured to be 2.4 nm. For comparison, the RMS roughness of the SiO2 substrate was 0.3 nm. When the thin-film nominal thickness is increased to 20 nm (20nm Au sample, Fig. 2c), the Au layer becomes continuous, but a certain degree of surface roughness is still present due to grain coalescence. The AFM image (Fig. 2d) shows an RMS surface roughness of 1.0 nm, which is significantly lower than the 2nm Au sample. | From the cross section profile of the 2nm Au sample (Fig. 2a), it is clear that Au, when deposited directly on SiO2, in order to reduce the interface energy, forms a nanoparticle-like layer in contrast to a continuous film. The diameter of the nanoparticles is about 10 nm. The nanoparticle morphology is confirmed by AFM analysis (Fig. 2b). The RMS surface roughness was measured to be 2.4 nm. For comparison, the RMS roughness of the SiO2 substrate was 0.3 nm. When the thin-film nominal thickness is increased to 20 nm (20nm Au sample, Fig. 2c), the Au layer becomes continuous, but a certain degree of surface roughness is still present due to grain coalescence. The AFM image (Fig. 2d) shows an RMS surface roughness of 1.0 nm, which is significantly lower than the 2nm Au sample. | ||
[[File:Picture1.png|350px|center|thumb|Fig. 2: TEM cross section images and 300x300 nm AFM images of the 2nm Au sample (a-b) and of the 20nm Au sample (c-d).]] | |||
From the TEM bright field cross section analysis of the 2nm Ti/2nm Au sample, it is observed that 2 nm of Ti forms a continuous layer below the Au layer (Fig. 3a). The Au layer is continuous over the Ti, indicating that Ti is responsible for an interface energy decrease, acting as an adhesive. The AFM analysis of the same sample confirmed the continuous structure, and an RMS surface roughness of 0.8 nm was measured (Fig. 3b). The 2nm Ti/20nm Au sample also shows a smoother film compared to the 20nm Au sample (Fig. 3c), and the AFM analysis shows an RMS surface roughness of 0.5 nm (Fig. 3d), very similar to the one of the Si substrate. | From the TEM bright field cross section analysis of the 2nm Ti/2nm Au sample, it is observed that 2 nm of Ti forms a continuous layer below the Au layer (Fig. 3a). The Au layer is continuous over the Ti, indicating that Ti is responsible for an interface energy decrease, acting as an adhesive. The AFM analysis of the same sample confirmed the continuous structure, and an RMS surface roughness of 0.8 nm was measured (Fig. 3b). The 2nm Ti/20nm Au sample also shows a smoother film compared to the 20nm Au sample (Fig. 3c), and the AFM analysis shows an RMS surface roughness of 0.5 nm (Fig. 3d), very similar to the one of the Si substrate. | ||
<gallery widths=" | <gallery widths="350px" heights="350px" perrow="2" halign="center"> image:Picture5.png|Fig. 3: TEM cross section images and 300x300 nm AFM images of the 2nm Ti/2nm Au sample (a-b) and of the 2nm Ti/20nm Au sample (c-d). | ||
image:Picture5.png|Fig. 3: TEM cross section images and 300x300 nm AFM images of the 2nm Ti/2nm Au sample (a-b) and of the 2nm Ti/20nm Au sample (c-d). | |||
image:Picture7.png|Fig. 4: TEM cross section images and 300x300 nm AFM images of the 2nm Cr/2nm Au sample (a-b) and of the 2nm Cr/20nm Au sample (c-d). </gallery> | image:Picture7.png|Fig. 4: TEM cross section images and 300x300 nm AFM images of the 2nm Cr/2nm Au sample (a-b) and of the 2nm Cr/20nm Au sample (c-d). </gallery> | ||