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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/Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Silicon_Oxide/Deposition_of_Silicon_Oxide_using_Lesker_sputter_tool click here]'''
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=Sputter deposition of SiO<sub>2</sub> using Sputter System (Lesker)=
=Sputter deposition of SiO<sub>2</sub> using Sputter-System (Lesker)=


SiO<sub>2</sub> can be sputter deposited with RF bias in the Sputter System (Lesker). You can find basic information about the pressure and max power to use and the expected deposition rate on the [[Specific_Process_Knowledge/Thin_film_deposition/Lesker|Equipment page]] here in LabAdviser. To see the deposition parameters used by others, look in the [http://labmanager.dtu.dk/function.php?module=Processlog&view=editlog&machid=244 Process Log] in LabManager. Below you will find deposition parameters and results of a study on the  surface roughness and oxide insulation quality of the deposited films.
SiO<sub>2</sub> can be sputter deposited in the Sputter-System (Lesker). You will find information on the pressure, max power and expected deposition rate on the [[Specific_Process_Knowledge/Thin_film_deposition/Lesker|Equipment page]] here in LabAdviser. To see the deposition parameters used by others, search the [http://labmanager.dtu.dk/function.php?module=Processlog&view=editlog&machid=244 Process Log] in LabManager.  


==Surface roughness optimization==
''By Bjarke Thomas Dalslet @Nanotech.dtu.dk''


The Lesker CMS 18 sputter system provides thin films of varying surface roughness. This roughness was verified to be dependent on the sputtered material, sputter mode (DC or RF) and the substrate bias strength. Other probable factors include sputter power and pressure. Below is a table of results for SiO<sub>2</sub>. Similar studies were carried out for Si and Ta.
==SiO<sub>2</sub> Reactive RF Sputtering from Si target==


The "From SiO<math>_2</math> target (RF sputter)" study was done on clean Si substrates. The sputter power was 157W and the pressure 3.5 mTorr using RF sputtering of a SiO<math>_2</math> target. The film thicknesses were around 42 nm.
This page presents the results of reactive SiO<sub>2</sub> deposition using <b>R-RF sputtering</b> with oxygen in Sputter-System Lesker, now commonly known as "Old Lesker". The deposition target is <b>Si</b>. Source #5 (RF) was used. R-RF SiO<sub>2</sub> is commonly used for the dielectric layers, especially if lift-off is needed.


===From SiO2 target (RF sputter)===
The fabrication and characterization described below were conducted in <b>18 of March 2022 by Evgeniy Shkondin, DTU Nanolab</b>. The prepared samples were investigated by the Spectroscopic Ellipsometry. The Sellmeier optical model is used. The focus of the study was the deposition conditions for possible backup in case of Cluster Lesker failure.
 
 
The process recipe in a Sputter-System (Lesker) is following:
 
 
* Deposition type: <b>R-RF</b>
* Power: <b>90 W</b>.
* Pressure: <b>3 mTorr</b>
* Gas: <b>10% of O<sub>2</sub> in Ar</b>
* Deposition time: <b>7200 s.</b>
* Temperature: 20&deg;C (no heating)
* Measured DC bias: 400V
 
Measured thickness: 170nm for 7200s (Measured by Spectroscopic Ellipsometry. The substrate used: 100mm Si wafer)
 
<br>
<!-- -->
* Deposition Rate: <b><span style="color: red">0.023 nm/s</span></b>
<br>
<!-- -->
 
 
<gallery caption="Uniformity measurements and optical function." widths="400px" heights="350px" perrow="2">
image:eves_SiO2_R-RF_old_Lesker_20220110.png| Uniformity across 100 wafer.
image:eves_refractive_index_SiO2_old_lesker_R-RF_20220718.png| Measured refractive index.
</gallery>
 
 
 
{| border="2" cellspacing="2" cellpadding="5"  align="center"
|-
!colspan="5" border="none" style="background:silver; color:black;" align="center"| Deposition results on 150mm wafers
|-
!Time (s)
|<b>Average thickness (nm)</b>
|<b>Standard deviation error</b>
|<b>Minimum thickness (nm)</b>
|<b>Maximum thickness (nm)</b>
 
|-
|7200
|168.85
|4.55
|163.21
|177.23
 
|-
|}
 
 
 
Two important notes:
 
* <b><span style="color: green">1</span></b>. Keep the pressure around 3 mTorr. If pressure increases to 5mTorr the deposition rate will suffer so practically the sputtering stops.
 
 
* <b><span style="color: green">2</span></b>. Do not increase oxygen levels above 10% for the same reason as above.
 
 
 
<br>
<!-- -->
 
==Non-reactive SiO<sub>2</sub> deposition from SiO<sub>2</sub> target==
 
SiO<sub>2</sub> can also be sputtered directly from SiO<sub>2</sub> target with RF bias assistance in the Sputter-System (Lesker).
 
Below you will find the deposition parameters and results of a study on the  surface roughness and oxide insulation quality of the sputtered SiO<sub>2</sub>.
 
===Surface roughness optimization===
''By <b>Bjarke Thomas Dalslet @Nanotech.dtu.dk</b>''
 
The Lesker CMS 18 sputter system provides thin films of varying surface roughness. This roughness was verified to be dependent on the sputtered material, sputter mode (DC or RF) and the substrate bias strength. Other probable factors include sputter power and pressure. Below is a table of results for SiO<sub>2</sub>. Similar studies were carried out for [http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Silicon/Si_sputter_in_Sputter-System_Lesker Si] and [http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Tantalum/Sputtering_of_Ta Ta].
 
The "SiO<sub>2</sub> target (RF sputter)" study was done on clean Si substrates. The sputter power was 157W and the pressure 3.5 mTorr using RF sputtering of a SiO<sub>2</sub> target. The film thicknesses were around 42 nm.
 
<b>From SiO<sub>2</sub> target (RF sputter)</b>
{| {{table}} border="1" cellspacing="0" cellpadding="8"
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Wafer nr'''
| align="center" style="background:#f0f0f0;"|'''Wafer nr'''
| align="center" style="background:#f0f0f0;"|'''RF bias (W)'''
| align="center" style="background:#f0f0f0;"|'''RF bias (W)'''
| align="center" style="background:#f0f0f0;"|'''Reactive O2 (%)'''
| align="center" style="background:#f0f0f0;"|'''Reactive O<sub>2</sub> (%)'''
| align="center" style="background:#f0f0f0;"|'''Power(W)'''
| align="center" style="background:#f0f0f0;"|'''Power(W)'''
| align="center" style="background:#f0f0f0;"|'''Rq (RMS) (nm)'''
| align="center" style="background:#f0f0f0;"|'''R<sub>q</sub> (RMS) (nm)'''
| align="center" style="background:#f0f0f0;"|'''Thickness'''
| align="center" style="background:#f0f0f0;"|'''Thickness (nm)'''
|-
|-
| 3||0||0||157||0.902||
| 3||0||0||157||0.902||
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<br>
<br>
==Oxide insulation analysis==
 
===Oxide insulation analysis===
''by Bjarke Thomas Dalslet @Nanotech.dtu.dk''
''by Bjarke Thomas Dalslet @Nanotech.dtu.dk''


The wafers in this analysis consisted of a Si substrate with no native oxide. A layer of SiO<math>_2</math> was reactively sputtered (9% O2 90 W 3.5 mTorr). After that, using a shadow mask, 200nm thick gold rectangles was electro deposited on top of the oxide. Gold was also electro deposited on the back side. Then the impedance as a function of frequency was recorded.
The wafers in this analysis consisted of a Si substrate with no native oxide. A layer of SiO<sub>2</sub> was reactively sputtered (9% O<sub>2</sub> 90 W 3.5 mTorr). After that, using a shadow mask, 200nm thick gold rectangles was electro deposited on top of the oxide. Gold was also electro deposited on the back side. Then the impedance as a function of frequency was recorded.


The figure shows the measurements for different oxide thicknesses. Most of the measurements show perfect capacitors, although for illustration measurements with a few pinholes and with many pinholes is also shown for the 20 nm sample.  
The figure shows the measurements for different oxide thicknesses. Most of the measurements show perfect capacitors, although for illustration measurements with a few pinholes and with many pinholes is also shown for the 20 nm sample.  
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<br>
<br>
==Tensile stress in SiO<sub>2</sub> films deposited at high temperature==
In 2017 Radu Malureanu deposited SiO<sub>2</sub> at 600 °C in order to obtain films with a high tensile stress. More information on this study can be found [[Specific_Process_Knowledge/Thin_film_deposition/Lesker/Stress_dependence_on_sputter_parameters_in_the_Lesker_sputter_system|here]].
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