Specific Process Knowledge/Etch/Wet III-V Etches: Difference between revisions

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'''Feedback to this page''': '''[mailto:labadviser@danchip.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.danchip.dtu.dk/index.php?title=Specific_Process_Knowledge/Etch/Wet_III-V_Etches click here]'''  
'''Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.'''


This is a collection of III-V wet-etches; not all etches are currently used at DTU Danchip why the rates should be tested before use. Make sure you have the proper education in mixing of chemicals before use.
'''All links to Kemibrug (SDS) and Labmanager Including APV and QC requires login.'''


It is utterly important that you dispose of chemicals/etches according to the DTU Danchip regulations; more information is found in the III-V cleanroom.
'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php?title=Specific_Process_Knowledge/Etch/Wet_III-V_Etches click here]'''


[[Category: Equipment|Etch Wet III-V]]
[[Category: Etch (Wet) bath|III-V]]
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:
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=374 Fume hood 07 Info page in LabManager]
<br>
It is very important that you dispose off chemicals and process waste according to DTU Nanolab regulations and risk assessments for your work.
[[Image:FH07.jpg|300x300px|right|thumb|'Fume hood 07' in cleanroom D3]]
<br>
For dry etching III-V materials see
*[[Specific Process Knowledge/Etch/III-V ICP|III-V ICP]]
*[[Specific Process Knowledge/Etch/III-V RIE|III-V RIE - Plassys]]
== InP or GaAs substrate etching ==
When etching InP or 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 two bottles in the fumehood one for HCl used to etch InP substrates and one for citric acid: H2O2 or H2SO4 (10%):H2O2 used to etch GaAs substrates.
Once the bottles are full, you should bring them in the basement of building 346 and have a new one in CR. '''For the GaAs waste you should use empty H2O2 bottles (since they should have a special lid that avoid overpressure)''', while for InP waste we can use an empty and clean developer bottle.


==HCl:H3PO4 etch==
==HCl:H3PO4 etch==


HCl(37%):H<sub>3</sub>PO<sub>4</sub>(85%) is a selective, anisotropic and slow etching of InP. Very slow rate in quarternaries. The etch rates depend on the orientation of the features and have not yet been calibrated at DTU Danchip.
HCl(37%):H<sub>3</sub>PO<sub>4</sub>(85%) is a selective, anisotropic and slow etching of InP. Very slow rate in InGaAsP. The etch rates depend on the orientation of the features and have not yet been calibrated at DTU Nanolab.


See rates below for InP, PQ(1.n) and InGaAs lattice-matched to InP. '''The acronym PQ(1.n) denotes a lattice-matched InGaAsP with a band gap corresponding to a wavelength of 1.n mm.'''  
See rates below for InP, PQ(1.n) and InGaAs lattice-matched to InP. '''The acronym PQ(1.n) denotes a lattice-matched InGaAsP on InP with a band gap corresponding to a wavelength of 1.n um.'''  


The temperature is 22 degC +/- 1 degC.
The temperature is 22 degC +/- 1 degC.


<!-- copyright issue rkc


{| border="1" style="text-align: center; width: 400px; height: 100px;"
{| border="1" style="text-align: center; width: 600px; height: 100px;"
! colspan="4" style="text-align: center;" style="background: #efefef;" | HCl(37%):H<sub>3</sub>PO<sub>4</sub>(85%) etch rates, nm/min
! colspan="5" style="text-align: center;" style="background: #efefef;" | HCl(37%):H<sub>3</sub>PO<sub>4</sub>(85%) etch rates, nm/min
|-
|-
! scope="row" width="20%" |Etchant
! scope="row" width="20%" |Etchant
Line 22: Line 44:
! width="20%" |PQ(1.1)
! width="20%" |PQ(1.1)
! width="20%" |InGaAs
! width="20%" |InGaAs
! width="20%" |Contributor
|-
|-
|1:4
|1:4
Line 27: Line 50:
|<2
|<2
|<1
|<1
|Before 2012 by Tine Greibe
|-
|1:0
|8700 +/- 500
|&nbsp;
|small
|2014-July by Luisa Ottaviano
|}
|}
<br>
-->


==H2SO4:H2O2:H2O etch==
==H2SO4:H2O2:H2O etch==


H<sub>2</sub>SO<sub>4</sub>(10%):H<sub>2</sub>O<sub>2</sub>(35%):H<sub>2</sub>O is a selective etch of InGaAsP with very low etch rate in InP. '''The acronym PQ(1.n) denotes a lattice-matched InGaAsP with a band gap corresponding to a wavelength of 1.n mm.'''  
H<sub>2</sub>SO<sub>4</sub>(10%):H<sub>2</sub>O<sub>2</sub>(30%):H<sub>2</sub>O is a selective etch of InGaAsP with very low etch rate in InP. '''The acronym PQ(1.n) denotes a lattice-matched InGaAsP on InP with a band gap corresponding to a wavelength of 1.n um.'''  


The etchrates have not yet been calibrated at DTU Danchip.
The etch rates have not yet been calibrated at DTU Nanolab.
The temperature is 22 degC +/- 1 degC.
The temperature is 22 degC +/- 1 degC.


<!-- copyright issue rkc


{| border="1" style="text-align: center; width: 500px; height: 100px;"
{| border="1" style="text-align: center; width: 800px; height: 100px;"
! colspan="6" style="text-align: center;" style="background: #efefef;" | H<sub>2</sub>SO<sub>4</sub>(10%):H<sub>2</sub>O<sub>2</sub>(35%):H<sub>2</sub>O etch rates, nm/min
! colspan="7" style="text-align: center;" style="background: #efefef;" | H<sub>2</sub>SO<sub>4</sub>(10%):H<sub>2</sub>O<sub>2</sub>(30%):H<sub>2</sub>O etch rates, nm/min
|-
|-
! scope="row" width="20%" |Etchant
! scope="row" width="15%" |Etchant
! width="20%" |InP
! width="10%" |InP
! width="20%" |PQ(1.1)
! width="15%" |PQ(1.1)
! width="20%" |PQ(1.3)
! width="15%" |PQ(1.3)
! width="20%" |PQ(1.5)
! width="15%" |PQ(1.5)
! width="20%" |InGaAs
! width="15%" |InGaAs
! width="100%" |Contributer
|-
|-
|1:1
|1:1:0 '''<sup>1</sup>'''
|<5
|<5
|<50
|<50
|230+/-70
|1000+/-500
|2700+/-1000
|Updated 2014-July by Luisa Ottaviano
|-
|10:8:71
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|500
|Updated 2014-July by Luisa Ottaviano
|-
|10:8:171
|&nbsp;
|&nbsp;
|&nbsp;
|&nbsp;
|180+/-20
|Updated 2014-July by Luisa Ottaviano
|}
|}
'''(1)''' The etch rates have not yet been calibrated at DTU Nanolab.
-->
<br>


==Concentrated H2SO4==
==Concentrated H2SO4==


Concentrated H<sub>2</sub>SO<sub>4</sub>(96%) is a selective etch of InP with a very low etch rate in InGaAsP.
Concentrated H<sub>2</sub>SO<sub>4</sub>(98%) is used for deoxidation of InP with a very low etch rate in InGaAsP.
 


{| border="1" style="text-align: center; width: 500px; height: 100px;"
{| border="1" style="text-align: center; width: 500px; height: 100px;"
! colspan="6" style="text-align: center;" style="background: #efefef;" | H<sub>3</sub>PO<sub>4</sub>(90%) etch rates, nm/min
! colspan="6" style="text-align: center;" style="background: #efefef;" | H<sub>2</sub>SO<sub>4</sub>(98%) etch rates, nm/min
|-
|-
! scope="row" width="20%" |Etchant
! scope="row" width="20%" |Etchant
Line 70: Line 125:
! width="20%" |InGaAs
! width="20%" |InGaAs
|-
|-
|H<sub>2</sub>SO<sub>4</sub>(96%)  
|H<sub>2</sub>SO<sub>4</sub>(98%)  
|13
|13
|?
|?
Line 77: Line 132:
|&nbsp;
|&nbsp;
|}
|}
|}
 
<BR>


==H3PO4:H2O2:H2O etch==
==H3PO4:H2O2:H2O etch==


H<sub>3</sub>PO<sub>4</sub>(85%):H<sub>2</sub>O<sub>2</sub>(35%):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.


<!-- copyright issue rkc


{| border="1" style="text-align: center; width: 500px; height: 100px;"
{| border="1" style="text-align: center; width: 500px; height: 100px;"
! colspan="4" style="text-align: center;" style="background: #efefef;" | H<sub>3</sub>PO<sub>4</sub>(85%):H<sub>2</sub>O<sub>2</sub>(35%):H<sub>2</sub>O etch rates, nm/min
! colspan="4" style="text-align: center;" style="background: #efefef;" | H<sub>3</sub>PO<sub>4</sub>(85%):H<sub>2</sub>O<sub>2</sub>(30%):H<sub>2</sub>O etch rates, nm/min
|-
|-
! scope="row" width="30%" |Etchant
! scope="row" width="30%" |Etchant
Line 105: Line 162:
|~600
|~600
|~600
|~600
|'''2,3'''
|'''2, 3'''
|}
|}


'''(1)''' Temperature of mixture is ~22 C (no heating during etch). data obtained using magnetic stirring with sample on flat basket. '''(2)''' Refrigerated H2O used during mixture of etch, and mixture kept at 17 C 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.
 
-->
 
<br>


==BHF etch==
==BHF, HF etch==


BHF etches SiO<sub>2</sub> and removes native oxide on InGaAs. '''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!'''.


<!-- copyright issue rkc


{| border="1" style="text-align: center; width: 500px; height: 100px;"
{| border="1" style="text-align: center; width: 500px; height: 100px;"
! colspan="4" style="text-align: center;" style="background: #efefef;" | BHF etch rates, nm/min
! colspan="5" style="text-align: center;" style="background: #efefef;" | BHF (12.5%), HF etch rates, nm/min
|-
|-
! scope="row" width="30%" |Etchant
! scope="row" width="15%" |Etchant
! width="20%" |SiO<sub>2</sub> '''<sup>1</sup>'''
! width="25%" |SiO<sub>2</sub>
! width="20%" |PECVD2 Si<sub>3</sub>N<sub>4</sub>
! width="20%" |PECVD2 Si<sub>3</sub>N<sub>4</sub>
! width="20%" |E-beam Ti '''<sup>2</sup>'''
! width="20%" |E-beam Ti '''<sup>1</sup>'''
! width="20%" |Al(x)GaAs, x>0.5, AlAs
|-
|-
|BHF 1:7
|BHF (12.5%)
|202
|283 '''<sup>2</sup>''', 175+/-25 '''<sup>3</sup>'''
|52
|88 '''<sup>4</sup>'''
 
|90-120
|90-120
|&nbsp;
|-
|HF:H<sub>2</sub>O
|&nbsp;
|&nbsp;
|&nbsp;
|>10000 '''<sup>5</sup>'''
|}
|}


'''(1)''' Process '''SiO2thi1''' in PECVD2. '''(2)''' Ti from Titest.prg on Physimeca. It seems there is no measurable etchig during first 10 seconds.
'''(1)''' Ti from Titest.prg on Physimeca. It seems there is no measurable etching during first 10 seconds.<br>
'''(2)''' Process '''SiO2ky2''' in PECVD2 (2014-July Luisa Ottaviamo @photonics ). <br>
'''(3)''' Process '''STANDARD''' in PECVD2 (2014-July Luisa Ottaviano @ photonics).<br>
'''(4)''' Process '''SINSTD''' in PECVD2 (2014-July Luisa Ottaviano @ photonics). <br>
'''(5)''' Appl. Phys. Lett. vol. 51, 2222 (1987).
<br>
<br>'''Note:''' neither Physimeca or PECVD2 is available anymore. Use the Temescal and the PECVD3/PECVD4 instead.
 
-->


==Citric Acid etch==
==Citric Acid etch==
Line 136: Line 213:
C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O<sub>2</sub> is a selective etch of GaAs; does not etch Al<sub>x</sub>Ga<sub>{1-x}</sub>As if x > 0.45.
C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O<sub>2</sub> is a selective etch of GaAs; does not etch Al<sub>x</sub>Ga<sub>{1-x}</sub>As if x > 0.45.


Solid C<sub>6</sub>H<sub>8</sub>O<sub>7</sub> is mixed 1:1 by weight with H<sub>2</sub>O using magnetic stirring. The solution C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O is thereafter mixed 4:1 volume ratio with H<sub>2</sub>O<sub>2</sub>.
Solid C<sub>6</sub>H<sub>8</sub>O<sub>7</sub> is mixed 1:1 by weight with H<sub>2</sub>O (30%) using magnetic stirring. The solution C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>:H<sub>2</sub>O is thereafter mixed 4:1 volume ratio with H<sub>2</sub>O<sub>2</sub>.


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 C.
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.

Latest revision as of 12:02, 7 February 2023

Unless anything else is stated, everything on this page, text and pictures are made by DTU Nanolab.

All links to Kemibrug (SDS) and Labmanager Including APV and QC requires login.

Feedback to this page: click here

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:

Fume hood 07 Info page in LabManager
It is very important that you dispose off chemicals and process waste according to DTU Nanolab regulations and risk assessments for your work.

'Fume hood 07' in cleanroom D3


For dry etching III-V materials see


InP or GaAs substrate etching

When etching InP or 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 two bottles in the fumehood one for HCl used to etch InP substrates and one for citric acid: H2O2 or H2SO4 (10%):H2O2 used to etch GaAs substrates. Once the bottles are full, you should bring them in the basement of building 346 and have a new one in CR. For the GaAs waste you should use empty H2O2 bottles (since they should have a special lid that avoid overpressure), while for InP waste we can use an empty and clean developer bottle.

HCl:H3PO4 etch

HCl(37%):H3PO4(85%) is a selective, anisotropic and slow etching of InP. Very slow rate in InGaAsP. The etch rates depend on the orientation of the features and have not yet been calibrated at DTU Nanolab.

See rates below for InP, PQ(1.n) and InGaAs lattice-matched to InP. The acronym PQ(1.n) denotes a lattice-matched InGaAsP on InP with a band gap corresponding to a wavelength of 1.n um.

The temperature is 22 degC +/- 1 degC.


H2SO4:H2O2:H2O etch

H2SO4(10%):H2O2(30%):H2O is a selective etch of InGaAsP with very low etch rate in InP. The acronym PQ(1.n) denotes a lattice-matched InGaAsP on InP with a band gap corresponding to a wavelength of 1.n um.

The etch rates have not yet been calibrated at DTU Nanolab. The temperature is 22 degC +/- 1 degC.


Concentrated H2SO4

Concentrated H2SO4(98%) is used for deoxidation of InP with a very low etch rate in InGaAsP.

H2SO4(98%) etch rates, nm/min
Etchant InP PQ(1.1) PQ(1.3) PQ(1.5) InGaAs
H2SO4(98%) 13 ? <1    


H3PO4:H2O2:H2O etch

H3PO4(85%):H2O2(30%):H2O is a GaAs/AlGaAs-etch which gives a better surface quality than H2SO4-based etches.



BHF, HF etch

BHF etches SiO2 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!.


Citric Acid etch

C6H8O7:H2O2 is a selective etch of GaAs; does not etch AlxGa{1-x}As if x > 0.45.

Solid C6H8O7 is mixed 1:1 by weight with H2O (30%) using magnetic stirring. The solution C6H8O7:H2O is thereafter mixed 4:1 volume ratio with H2O2.

The above C6H8O7:H2O2 solution has an etch-rate of ~360 nm/min in GaAs and < 0.5 nm/min in AlAs @ 25 degC.

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