Jump to content

Specific Process Knowledge/Thin Film deposition/ALD/TiO2 deposition using ALD: Difference between revisions

← Older editNewer edit →
VisualWikitext
Pevo (talk | contribs)
DCH-Employees-701, NLAB-Employees-701, NLAB-LabmanagerAllUsers
2,331 edits
No edit summary
Pevo (talk | contribs)
DCH-Employees-701, NLAB-Employees-701, NLAB-LabmanagerAllUsers
2,331 edits
No edit summary
Line 6: Line 6:
The ALD window for titanium dioxide (TiO<sub>2</sub>) ranges from 120 <sup>o</sup>C to 350 <sup>o</sup>C.  
The ALD window for titanium dioxide (TiO<sub>2</sub>) ranges from 120 <sup>o</sup>C to 350 <sup>o</sup>C.  


A low temperatures between 120 <sup>o</sup>C and 150 <sup>o</sup>C an anatase TiO<sub>2</sub> layer is grow in the ALD, and at higher temperatures between 300 <sup>o</sup>C and 350 <sup>o</sup>C an amorphous TiO<sub>2</sub> layer is grown in the ALD. At temperatures between 150 <sup>o</sup>C and 300 <sup>o</sup>C the TiO<sub>2</sub> layer will be a mixture of both anatase and amorphous TiO<sub>2</sub>.
A low temperatures between 120 <sup>o</sup>C and 150 <sup>o</sup>C an anatase TiO<sub>2</sub> layer is grown in the ALD, and at higher temperatures between 300 <sup>o</sup>C and 350 <sup>o</sup>C an amorphous TiO<sub>2</sub> layer is grown. At temperatures between 150 <sup>o</sup>C and 300 <sup>o</sup>C the TiO<sub>2</sub> layer will be a mixture of both anatase and amorphous TiO<sub>2</sub>.


For Si wafers, anatase TiO<sub>2</sub> is best grown on wafers without native oxide (removed using BHF), and amorphous TiO<sub>2</sub> is best grown on wafers with native oxide.
For Si wafers, anatase TiO<sub>2</sub> is best grown on wafers without native oxide (removed using BHF), and amorphous TiO<sub>2</sub> is best grown on wafers with native oxide.


XPS measurements shows that at temperaturs below 120 <sup>o</sup>C the TiO<sub>2</sub> layer will be contaminated with about 1-3 % chlorine molecules from the TiCl<sub>4</sub> precursor.
XPS measurements shows that at temperaturs below 120 <sup>o</sup>C the TiO<sub>2</sub> layer will be contaminated with about 1-3 % chlorine molecules from the TiCl<sub>4</sub> precursor. This can be seen as small white dots in SEM images of the anatase TiO<sub>2</sub> layers.
 


<b>Recipe</b>: TiO2
<b>Recipe</b>: TiO2
Line 38: Line 39:




In the graphs below the TiO<sub>2</sub> thickness as function of number of cycles for deposition temperatures between 150 <sup>o</sup>C and 350 <sup>o</sup>C can be seen. From the equations the number of cycles required for a certain thickess can be calculated.  
In the graphs below the TiO<sub>2</sub> thickness as function of the number of cycles for deposition temperatures between 150 <sup>o</sup>C and 350 <sup>o</sup>C can be seen. From the equations the number of cycles required for a certain thickess can be calculated.  


<gallery caption="Titanium dioxide thickness as function of number of cycles" widths="220px" heights="220px" perrow="5">
<gallery caption="Titanium dioxide thickness as function of number of cycles" widths="300px" heights="300px" perrow="5">
image:ALD_TiO2_grow_rate_150C.jpg| Temperature 150 <sup>o</sup>C.
image:ALD_TiO2_grow_rate_150C.jpg| Temperature 150 <sup>o</sup>C.
image:ALD_TiO2_grow_rate_250C.jpg| Temperature 200 <sup>o</sup>C.
image:ALD_TiO2_grow_rate_250C.jpg| Temperature 200 <sup>o</sup>C.
image:ALD_TiO2_grow_rate_350C.jpg| Temperature 250 <sup>o</sup>C.
image:ALD_TiO2_grow_rate_350C.jpg| Temperature 250 <sup>o</sup>C.
</gallery>
</gallery>
SEM images of both anatase and amorphous TiO<sub>2</sub> are shown below.


Below some SEM images of anatase TiO<sub>2</sub> deposited at 120 <sup>o</sup>C on Si trenches are shown. The width of the trenches is 200 nm, and the depth is 4 µm, i.e. the aspect ratio is 1:20. The number of cycles is 500, and this results in a TiO<sub>2</sub> layer of about 25 nm. From the SEM images it is seen that the TiO<sub>2</sub> layer covers the trenches very well.  
Below some SEM images of anatase TiO<sub>2</sub> deposited at 120 <sup>o</sup>C on Si trenches are shown. The width of the trenches is 200 nm, and the depth is 4 µm, i.e. the aspect ratio is 1:20. The number of cycles is 500, and this results in a TiO<sub>2</sub> layer of about 25 nm. From the SEM images it is seen that the TiO<sub>2</sub> layer covers the trenches very well.  
Line 58: Line 55:
</gallery>
</gallery>


Below some SEM images of anatase TiO<sub>2</sub> deposited at 300 <sup>o</sup>C on Si trenches are shown. The width of the trenches is 200 nm, and the depth is 4 µm, i.e. the aspect ratio is 1:20. The number of cycles is 500, and this results in a TiO<sub>2</sub> layer of about 26 nm. From the SEM images it is seen that the TiO<sub>2</sub> layer covers the trenches very well.  
Below some SEM images of amorphous TiO<sub>2</sub> deposited at 300 <sup>o</sup>C on Si trenches are shown. The width of the trenches is 200 nm, and the depth is 4 µm, i.e. the aspect ratio is 1:20. The number of cycles is 500, and this results in a TiO<sub>2</sub> layer of about 26 nm. From the SEM images it is seen that the TiO<sub>2</sub> layer covers the trenches very well.  


<gallery caption="" widths="250px" heights="250px" perrow="5">
<gallery caption="" widths="250px" heights="250px" perrow="5">
Retrieved from "https://labadviser.nanolab.dtu.dk//index.php?title=Specific_Process_Knowledge/Thin_Film_deposition/ALD/TiO2_deposition_using_ALD"