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The ALD window for titanium dioxide (TiO₂) ranges from 120 ^oC to 350 ^oC.

A low temperatures between 120 ^oC and 150 ^oC an anatase TiO₂ layer is grow in the ALD, and at higher temperatures between 300 ^oC and 350 ^oC an amorphous TiO₂ layer is grown in the ALD. At temperatures between 150 ^oC and 300 ^oC the TiO₂ layer will be a mixture of both anatase and amorphous TiO₂.

For Si wafers, anatase TiO₂ is best grown on wafers without native oxide (removed using BHF), and amorphous TiO₂ is best grown on wafers with native oxide.

XPS measurements shows that at temperaturs below 120 ^oC the TiO₂ layer will be contaminated with about 1-3 % chlorine molecules from the TiCl₄ precursor.

Recipe: TiO2

Temperature: 120 ^oC - 350 ^oC

	TiCl₃	H₂O
Nitrogen flow	150 sccm	200 sccm
Pulse time	0.1 s	0.1 s
Purge time	3.0 s	4.0 s

In the graphs below the TiO₂ thickness as function of number of cycles for deposition temperatures between 150 ^oC and 350 ^oC can be seen. From the equations the number of cycles required for a certain thickess can be calculated.

Titanium dioxide thickness as function of number of cycles
Temperature 150 ^oC.
Temperature 200 ^oC.
Temperature 250 ^oC.

SEM images of both anatase and amorphous TiO₂ are shown below.

Below some SEM images of anatase TiO₂ deposited at 120 ^oC 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 TiO₂ layer of about 25 nm. From the SEM images it is seen that the TiO₂ layer covers the trenches very well.

Below some SEM images of anatase TiO₂ deposited at 300 ^oC 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 TiO₂ layer of about 26 nm. From the SEM images it is seen that the TiO₂ layer covers the trenches very well.

Evgeniy Shkondin, DTU Danchip, 2014.

@@ 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.
-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 and 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 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>.
-SEM images of both anatase and amorphous TiO<sub>2</sub> are shown below.
+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 wafers without native oxide (do an BHF etch), 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.
-All results shown on this page have been obtained using the "TiO2" recipe on new Si(100) wafers with native oxide:
 <b>Recipe</b>: TiO2
-<b>Temperature</b>: 150 <sup>o</sup>C - 350 <sup>o</sup>C
+<b>Temperature</b>: 120 <sup>o</sup>C - 350 <sup>o</sup>C
 {| border="2" cellspacing="2" cellpadding="5"  align="none"
 |-
 |
-!TMA
+!TiCl<sub>3</sub>
 !H<sub>2</sub>O
 |-
@@ Line 49: / Line 40: @@
 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.
-<gallery caption="Titanium oxide 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="220px" heights="220px" perrow="5">
 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.
@@ Line 55: / Line 46: @@
 </gallery>
-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 \mum, 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.
+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.
 <gallery caption="" widths="250px" heights="250px" perrow="5">
@@ Line 63: / Line 58: @@
 </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 \mum, 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 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.
 <gallery caption="" widths="250px" heights="250px" perrow="5">