Specific Process Knowledge/Etch/Aluminum Oxide/Al2O3 Etch using HF: Difference between revisions

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Si samples with about 100 nm of [[Specific_Process_Knowledge/Thin_film_deposition/ALD_Picosun_R200|ALD]] deposited Al₂O₃ (1000 cycles at 300^oC) has been etched in different HF concentrations. After the etching, the thickness of the Al₂O₃ layer has been measured using [[Specific_Process_Knowledge/Characterization/Optical_characterization#Ellipsometer|Ellipsometer VASE]], and the thickness as function of time has been plotted as shown in the graph below.

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image:Al2O3_HF_20190826.png| Different etching rates for different HF concentrations.

<li><p>5% HF &#8594; <b>1.74 nm/s</b></p></li>

<li><p> 1vol. H₂O : 1vol. 5% HF &#8594; <b>1.05 nm/s</b></p></li>

<li><p> 2vol. H₂O : 1vol. 5% HF &#8594; <b>0.72 nm/s</b></p></li>

Be aware of that the 5% HF etches quite fast. Actually, so fast that it can be tricky to control. Taking the sample out of the solution and placing it in a bigger water container to rinse, resulting a time delay due to the movement and the etch continues. It means the handling things around the fumehood can be a source of errors in this case.