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Specific Process Knowledge/Thin film deposition/Deposition of Gold/Adhesion layers: Difference between revisions

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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>


To investigate the crystal orientation of the metal thin-�lms, tramsimission Kikuchi diffraction was used (Fig. 5a) (see [[LabAdviser/CEN/Nova NanoSEM 600/Transmission Kikuchi diffraction|Transmission Kikuchi diffraction]] for more information). The nanostructure of the 20nm Au �lm has a bimodal grain
To investigate the crystal orientation of the metal thin-films, tramsimission Kikuchi diffraction was used (Fig. 5a) (see [[LabAdviser/CEN/Nova NanoSEM 600/Transmission Kikuchi diffraction|Transmission Kikuchi diffraction]] for more information). The nanostructure of the 20nm Au film has a bimodal grain size distribution (Fig. 5b). While the smaller grains have different crystal orientations, the large grains (blue color) all have [111] orientation.
size distribution (Fig. 5b). While the smaller grains have di�erent crystal orientations, the large grains (blue color) all have [111] orientation. Microstructural evolution and growth of metal thin-�lms deposited by physical vapor deposition on amorphous dielectric substrates follows island growth. The �rst thin-�lm growth step is the nucleation of small islands once the activation barrier and the critical nuclei size have been overcome. It is followed by a second step of island growth, during which the impinging atoms contribute to increase island size. The third step, usually happening simultaneously with step 2, is island coalescence, where a strong driving force is present for coarsening through surface atom di�usion and grain boundaries (GB) motion. During this process, the island growth is driven by the minimization of surface and interface energy.
Fig. 5.4a represents two Au islands having di�erent crystal orientations. In
particular they have the (111)- and (100)-facets, respectively, parallel to the
substrate surface. The growth of these islands is dependent on their orientation
(Fig. 5.4b): for Au, which has a face-centered cubic unit cell, the (100)
surface has a higher surface energy than the (111) surface, and to minimize
energy, the (100) surface grows faster. Islands having (100) or (110) facets
parallel to the substrate grow faster in the vertical direction, while islands
with (111) facets parallel to the substrate grow faster laterally. The result


is a continuous �lm, having laterally larger and
Microstructural evolution and growth of metal thin-films deposited by physical vapor deposition on amorphous dielectric substrates follows island growth. The first thin-film growth step is the nucleation of small islands once the activation barrier and the critical nuclei size have been overcome. It is followed by a second step of island growth, during which the impinging atoms contribute to increase island size. The third step, usually happening simultaneously with step 2, is island coalescence, where a strong driving force is present for coarsening through surface atom diffusion and grain boundaries (GB) motion. During this process, the island growth is driven by the minimization of surface and interface energy.
atter islands with [111]
crystal direction, and laterally smaller but taller islands with [100] and [110]
orientations [106].


Fig. 6a represents two Au islands having different crystal orientations. In particular they have the (111)- and (100)-facets, respectively, parallel to the substrate surface. The growth of these islands is dependent on their orientation (Fig. 6b): for Au, which has a face-centered cubic unit cell, the (100) surface has a higher surface energy than the (111) surface, and to minimize energy, the (100) surface grows faster. Islands having (100) or (110) facets parallel to the substrate grow faster in the vertical direction, while islands with (111) facets parallel to the substrate grow faster laterally. The result is a continuous film, having laterally larger and flatter islands with [111] crystal direction, and laterally smaller but taller islands with [100] and [110] orientations.


<gallery widths="350px" heights="350px" perrow="2" halign="center"> image:Picture2.png|Fig. 5: TKD inverse pole �gure z-direction (IPFZ) map of the growth direction (a) and grain size distribution (b) of the 20nm Au sample.
image:Picture3.png|Fig. 6: (a) Schematic representation of [111] and [100] Au islands on a SiO2 substrate. The crystal direction is referred parallel to the substrate surface. (b) Representation of the orientation-driven growth of the islands on the substrate: the {100} facets grow faster than {111} ones in order to decrease surface energy. </gallery>


The samples with 20 nm Au layer were analyzed with TKD. The addition
The samples with the adhesion layers and 20 nm Au layer were also analyzed. The addition of the adhesion layer had in both cases a profound impact on grain size and orientation of the Au �lm, as visible in Fig. 5.7a and 5.7c. The image shows
of the adhesion layer had in both cases a profound impact on grain size and
orientation of the Au �lm, as visible in Fig. 5.7a and 5.7c. The image shows


small grains mainly oriented in the [111] crystal direction, with an average
small grains mainly oriented in the [111] crystal direction, with an average
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