I deposited TiO2 thin film on Si substrate. Substrate was etched to remove Silicon oxide layer before deposition but it develops oxide layer as soon as it is exposed to air. I need to have CV measurements of the sample which has TiO2 thin film on one side of Si substrate and Silicon oxide on the other side. in order to study it for CV measurements I need to deposit gold film on both sides but the main issue is to remove oxide layer. Can any one suggest some quick and east way to remove oxide layer from the Si wafer without damaging TiO2 thin film
Hello,
You can minimize the oxide silicon by an immersion in acid fluorhydrique (2%).
Given that silicion is well reactiv with oxygen in the air atmospheric. As consequence, you should select an elebaration technic for TiO2 prevent the Si oxidation.
Best regards
You can use a simple chemical method, you have to do an immersion of your substrate in diluted 10% HF(48%) solution for 2 minutes.
But you should be careful while using HF and remember the surface will re-oxidize reasonably fast so you need to get it into the vacuum chamber and pump down asap.
But it is already coated with TiO2 if I immerse it into HF it will remove TiO2 too
No,
You immerse the silicon sample in diluted HF solution. Then, you depose the TiO2 layer. It's interesting to depose TiO2 in vacuum or in Argon (the technics are Physical vapor deposition, Molecular Beam Epitaxy ...). The vacuum or argon is necessary to prevent the native re-oxidized.
Best regards.
when we manipulate silicon wafers, it is often suggested to programm all the operation steps within sight in one day, it means that, if you have to deposit TiO2 layer (which is a good antireflection coating to silicon) it is usueful to etch the silicon surface in 10% HF (48%) during 1-2 min just prior the TiO2 deposition, TiO2 is usually deposited by sol gel method. otherwise you will always have the native SiO2 if you plan to do both steps (etching and deposition) with a certain time interval.
Take double sided polished silicon wafer.
Oxidise it to SiO2. you get sio2 on both sides (1 and 2).
On side one put some black wax coating on side 1, and then etch the side 2, and remove the Sio2 layer till you get a clean silicon surface on side 2.
Go ahead and remove the black wax coating on side 1.
Now take this wafer and put it in the sputtering system, side 2 facing the target (TiO2)
Try to substrate sputter cleaning (insitu) the side 2 to remove any native oxide layers at a low rf power. The try to deposit your TiO2 layer.
Now this is one method of getting SiO2 on one side of Si wafer, and TiO2 on the other side.
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If you are trying to deposit tiO2 with sol gel method it is difficult to get both the oxides on either side of the wafer, and avoid sio2 layer under the TiO2 layer.
Sreenivas
I think you can not remove the oxide layer completely. if you somehow able to do so.. It will not remain for long.
Diluted HF 48% for 10-20 minutes. Depending on the oxidation level of your Si slices, after etching in HF check for the surface wettability. If the oxide layer was well removed the surface wettabilty is almost zero.
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