Specific Process Knowledge/Etch/Wet III-V Etches: Difference between revisions
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This is a collection of III-V wet-etches; the rates should be tested before use. Make sure you have the proper education in mixing of chemicals before use. Wet etching of III-V materials is primarily to be done in 'Fume hood 07: III-V acids/bases'. Contact information, risk assessment and manual regarding this fume hood can be found in LabManager: | This is a collection of III-V wet-etches; the rates should be tested before use. Make sure you have the proper education in mixing of chemicals before use. Wet etching of III-V materials is primarily to be done in 'Fume hood 07: III-V acids/bases'. Contact information, risk assessment and manual regarding this fume hood can be found in LabManager: | ||
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For dry etching III-V materials see | For dry etching III-V materials see | ||
*[[Specific Process Knowledge/Etch/III-V ICP|III-V ICP]] | *[[Specific Process Knowledge/Etch/III-V ICP|III-V ICP]] | ||
*[[Specific Process Knowledge/Etch/III-V RIE|III-V RIE - Plassys]] | *[[Specific Process Knowledge/Etch/III-V RIE|III-V RIE - Plassys]] (will be decommissioned October 2025) | ||
There should be | == InP substrate etching == | ||
Once the | |||
When etching InP substrates, both 2” wafers and small pieces, you should collect the used chemicals in a waste bottle. This does not apply for etching epilayers. | |||
There should be a bottle in the fumehood for HCl used to etch InP substrates. | |||
Once the bottle is full, it should be brought to the basement of building 346 and a new one placed in the CR. For InP waste a clean and empty developer bottle can be used. | |||
== GaAs substrate etching == | |||
When etching GaAs substrates, both 2” wafers and small pieces, you should collect the used chemicals in a waste bottle. This does not apply for etching epilayers. | |||
There should be a bottle in the fumehood for citric acid: H2O2 or H2SO4 (10%):H2O2 used to etch GaAs substrates. | |||
Once the bottle is full, it should be brought to the basement of building 346 and a new one placed in the CR. '''For the GaAs waste you should use empty H2O2 bottles (since they should have a special lid that avoid over pressure).''' | |||
==HCl:H3PO4 etch== | ==HCl:H3PO4 etch== | ||
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H<sub>3</sub>PO<sub>4</sub>(85%):H<sub>2</sub>O<sub>2</sub>(30%):H<sub>2</sub>O is a GaAs/AlGaAs-etch which gives a better surface quality than H<sub>2</sub>SO<sub>4</sub>-based etches. | H<sub>3</sub>PO<sub>4</sub>(85%):H<sub>2</sub>O<sub>2</sub>(30%):H<sub>2</sub>O is a GaAs/AlGaAs-etch which gives a better surface quality than H<sub>2</sub>SO<sub>4</sub>-based etches. | ||
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'''(1)''' Temperature of mixture is ~22 degC (no heating during etch). Data is obtained using magnetic stirring with sample on flat basket. '''(2)''' Refrigerated H2O used during mixture of etch, and mixture kept at 17 degC during etch. '''(3)''' 10:2:30 gives smoother etch than 10:2:60. | '''(1)''' Temperature of mixture is ~22 degC (no heating during etch). Data is obtained using magnetic stirring with sample on flat basket. '''(2)''' Refrigerated H2O used during mixture of etch, and mixture kept at 17 degC during etch. '''(3)''' 10:2:30 gives smoother etch than 10:2:60. | ||
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BHF etches SiO<sub>2</sub> and partially removes native oxide on InGaAs and InP. '''Do not use BHF unless you know the dangers involved with this chemical and always use 4H gloves!'''. | BHF etches SiO<sub>2</sub> and partially removes native oxide on InGaAs and InP. '''Do not use BHF unless you know the dangers involved with this chemical and always use 4H gloves!'''. | ||
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'''(5)''' Appl. Phys. Lett. vol. 51, 2222 (1987). | '''(5)''' Appl. Phys. Lett. vol. 51, 2222 (1987). | ||
<br> | <br> | ||
<br>'''Note:''' neither Physimeca or PECVD2 is available anymore. Use the Temescal and the PECVD3/PECVD4 instead. | <br>'''Note:''' neither Physimeca or PECVD2 is available anymore. Use the Temescal and the PECVD3/PECVD4 instead. | ||
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==Citric Acid etch== | ==Citric Acid etch== | ||
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The above C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O<sub>2</sub> solution has an etch-rate of ~360 nm/min in GaAs and < 0.5 nm/min in AlAs @ 25 degC. | The above C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O<sub>2</sub> solution has an etch-rate of ~360 nm/min in GaAs and < 0.5 nm/min in AlAs @ 25 degC. | ||
==More info regarding etching of III-V materials== | |||
More info on etching of III-V materials (not the DTU Nanolab wiki) can be found here: | |||
https://wiki.nanofab.ucsb.edu/wiki/Wet_Etching_Recipes '''(at the UCSB Nanofab Wiki)''' | |||
and | |||
https://www.sciencedirect.com/science/article/pii/S0927796X00000279 '''(at the UCSB Nanofab Wiki)''' | |||