Specific Process Knowledge/Thin film deposition/ALD2 (PEALD)/AlN deposition using ALD2: Difference between revisions

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'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/ALD2_(PEALD)/AlN_deposition_using_ALD2 click here]'''
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''This page is written by DTU Nanolab internal''
=General Information=
=General Information=
The AlN process should never run above 350 °C due to the decomposition of the trimethylaluminium.
The AlN process should never run above 350 °C due to the decomposition of the trimethylaluminium.
As already mentioned in the general ALD2 (PEALD) page oxides and nitrides cannot be deposited at the same time. Since the aluminium nitride requires the plasma source we only run all nitride processes without the thermal lid.
As already mentioned in the general ALD2 (PEALD) page oxides and nitrides cannot be deposited at the same time. Since the aluminium nitride requires the plasma source, we run all plasma processes without the thermal lid. The substrate temperature is around 50 °C lower than the setpoint, because the chamber volume becomes bigger without the thermal lid.
Hence the chamber volume is bigger than with the thermal lid which causes that the substrate temperature is around 50 °C lower than the setpoint.
 
=Result from acceptance test=


=Results from the acceptance test=


* [[Specific Process Knowledge/Thin film deposition/ALD Picosun R200/AlN deposition using ALD2/Acceptance_test_AlN|<b>results from the acceptance test (old material) </b>]].
During the acceptance test, AlN was deposited using TMA and N<sub>2</sub> plasma. We have modified and improved recipes since.
* [[Specific Process Knowledge/Thin film deposition/ALD2 (PEALD)/AlN deposition using ALD2/Acceptance_test_AlN|<b>results from the acceptance test (old material) </b>]].


=Deposition of AlN using TMA and NH3 plasma=
=Deposition of AlN using TMA and NH3 plasma=
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<b>Note!</b> Remember to obey the relation: [Pulse time - (t<sub>1</sub>+t<sub>2</sub>)] > 0.5 s
<b>Note!</b> Remember to obey the relation: [Pulse time - (t<sub>1</sub>+t<sub>2</sub>)] > 0.5 s


<gallery caption="" widths="500px" heights="400px" perrow="2">
image:eves_20200609_AlN_NH3_dep_rate.png| Deposition function for AlN with NH<sub>3</sub> plasma (350 &deg;C)
image:eves_20200609_AlN_NH3_SEM.png| Deposition of AlN with NH<sub>3</sub> plasma (500 cycles, 350 &deg;C) on si trench template. It is worth mention, that the process will not be good to passivate structures with an aspect ratio above 10.
</gallery>


<b>Evgeniy Shkondin, DTU Nanolab, 2020.</b>


==Spectroscopic ellipsometry==
==Spectroscopic ellipsometry==
The spectroscopic ellipsometry measurements were conducted by using [[Specific Process Knowledge/Characterization/Optical characterization|VASE Ellipsometer]]. The purpose of the investigation is to evaluate refractive index and dielectric function as well as to analyse the growth rate and uniformity.


===Refractive index and permittivity===
===Refractive index and permittivity===
<gallery caption="" widths="500px" heights="400px" perrow="2">
image:eves_20200609_AlN_NH3_refractive_index.png| Refractive index and absorption koefficient as a function of wavelength.
image:eves_20200609_AlN_NH3_permittivity.png| Real and imaginary permittivity as a function of wavelength.
</gallery>


===Thickness distribution and uniformity===
===Thickness distribution and uniformity===




<gallery caption="" widths="500px" heights="500px" perrow="3">
<gallery caption="" widths="500px" heights="400px" perrow="3">
image:eves_20200608_AlN_NH3_500cycles_SE_uniformity.png| Thickness distribution across the 100 mm wafer (350C 500cycles)
image:eves_20200608_AlN_NH3_500cycles_SE_uniformity.png| Thickness distribution across the 100 mm wafer (350C 500cycles)
image:eves_20200608_AlN_NH3_568cycles_SE_uniformity.png| Thickness distribution across the 100 mm wafer (350C 568cycles)
image:eves_20200608_AlN_NH3_568cycles_SE_uniformity.png| Thickness distribution across the 100 mm wafer (350C 568cycles)
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|}
|}




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==X-ray photoelectron spectroscopy==
==X-ray photoelectron spectroscopy==


XPS measurements of all samples has been performed using [[Specific Process Knowledge/Characterization/XPS/K-Alpha |XPS K-Alpha equipment]]. The purpose of the investigation is to get idea about film stoichiometry and possible contamination.


===Stoichiometry===
===Stoichiometry===
{| border="2" cellspacing="2" cellpadding="5"  align="center"
|-
!colspan="6" border="none" style="background:silver; color:black;" align="center"| Stoichiometry results for AlN deposited with TMA and NH<sub>3</sub> plasma
|-
|style="background:WhiteSmoke; color:black"|<b>Number of cycles</b>
|style="background:WhiteSmoke; color:black"|<b>568</b>
|style="background:WhiteSmoke; color:black"|<b>852</b>
|style="background:WhiteSmoke; color:black"|<b>1136</b>
|style="background:WhiteSmoke; color:black"|<b>1704</b>
|style="background:WhiteSmoke; color:black"|<b>2272</b>
|-
|style="background:WhiteSmoke; color:black"|<b>Average thickness (nm)</b>
|style="background:WhiteSmoke; color:black"|66.18
|style="background:WhiteSmoke; color:black"|103.83
|style="background:WhiteSmoke; color:black"|128.13
|style="background:WhiteSmoke; color:black"|203.66
|style="background:WhiteSmoke; color:black"|298.12
|-
|<b>Al (at.%)</b>
|47.54
|48.15
|47.82
|47.77
|47.61
|-
|<b>N (at.%)</b>
|40.80
|40.60
|41.13
|41.01
|41.11
|-
|<b>O (at.%)</b>
|11.66
|11.25
|11.05
|11.22
|11.28
|}


===Presence of Oxygen and Carbon===
===Presence of Oxygen and Carbon===
Traces of carbon is found in the deposited films, their origine is not clear, but most likely due to TMA decomposition. Another source is incomplete ALD reaction.
Oxygen is present in the film (up to 11 at.%)
<gallery caption="" widths="500px" heights="400px" perrow="2">
image:eves_20200609_AlN_NH3_XPS_C1s.png| C1s signal
image:eves_20200609_AlN_NH3_XPS_O1s.png| O1s signal
</gallery>
<gallery caption="" widths="500px" heights="350px" perrow="2">
image:eves_20200609_AlN_NH3_XPS_3D_C1s.png| C1s signal
image:eves_20200609_AlN_NH3_XPS_3D_O1s.png| O1s signal
</gallery>
<b>Evgeniy Shkondin, DTU Nanolab, 2020.</b>

Latest revision as of 13:10, 19 June 2023

Feedback to this page: click here

This page is written by DTU Nanolab internal


General Information

The AlN process should never run above 350 °C due to the decomposition of the trimethylaluminium. As already mentioned in the general ALD2 (PEALD) page oxides and nitrides cannot be deposited at the same time. Since the aluminium nitride requires the plasma source, we run all plasma processes without the thermal lid. The substrate temperature is around 50 °C lower than the setpoint, because the chamber volume becomes bigger without the thermal lid.

Results from the acceptance test

During the acceptance test, AlN was deposited using TMA and N2 plasma. We have modified and improved recipes since.

Deposition of AlN using TMA and NH3 plasma

Recipe name: AlN NH3 plasma

Temperature window: 250 °C - 350 °C

The deposition rate is measure to be 0.137 nm/cycle for 350 °C with growth delay of 144 cycles.

TMA NH3
Nitrogen flow 100 sccm 150 sccm
Pulse time 0.1 s 5 s
Purge time 8 s 30 s


Plasma source settings
RF power (W) Ar carrier flow (sccm) Plasma gas flow (sccm) t1 stabilization (s) t2 RF Power on (s)
3000 150 100 1 3.4


Note! Remember to obey the relation: [Pulse time - (t1+t2)] > 0.5 s

  • Deposition function for AlN with NH3 plasma (350 °C)
    Deposition function for AlN with NH3 plasma (350 °C)
  • Deposition of AlN with NH3 plasma (500 cycles, 350 °C) on si trench template. It is worth mention, that the process will not be good to passivate structures with an aspect ratio above 10.
    Deposition of AlN with NH3 plasma (500 cycles, 350 °C) on si trench template. It is worth mention, that the process will not be good to passivate structures with an aspect ratio above 10.

Evgeniy Shkondin, DTU Nanolab, 2020.

Spectroscopic ellipsometry

The spectroscopic ellipsometry measurements were conducted by using VASE Ellipsometer. The purpose of the investigation is to evaluate refractive index and dielectric function as well as to analyse the growth rate and uniformity.


Refractive index and permittivity

  • Refractive index and absorption koefficient as a function of wavelength.
    Refractive index and absorption koefficient as a function of wavelength.
  • Real and imaginary permittivity as a function of wavelength.
    Real and imaginary permittivity as a function of wavelength.

Thickness distribution and uniformity

  • Thickness distribution across the 100 mm wafer (350C 500cycles)
    Thickness distribution across the 100 mm wafer (350C 500cycles)
  • Thickness distribution across the 100 mm wafer (350C 568cycles)
    Thickness distribution across the 100 mm wafer (350C 568cycles)
  • Thickness distribution across the 100 mm wafer (350C 852cycles)
    Thickness distribution across the 100 mm wafer (350C 852cycles)
  • Thickness distribution across the 100 mm wafer (350C 1136cycles)
    Thickness distribution across the 100 mm wafer (350C 1136cycles)
  • Thickness distribution across the 100 mm wafer (350C 1704cycles)
    Thickness distribution across the 100 mm wafer (350C 1704cycles)
  • Thickness distribution across the 100 mm wafer (350C 2272cycles)
    Thickness distribution across the 100 mm wafer (350C 2272cycles)


Ellipsometry results for AlN deposited with TMA and NH3 plasma
Number of cycles Temperature (°C) Average thicknes (nm) Minimum thickness (nm) Maximum thickness (nm) Standard deviation Procent deviation (%)
500 350 42.9565 41.7422 43.4888 0.42652 2.0331
568 350 66.1824 64.2685 67.4074 0.7256 2.3714
852 350 103.8306 100.8147 106.1143 1.2407 2.552
1136 350 128.1302 124.8565 131.037 1.444 2.4118
1704 350 203.6618 198.1933 210.8584 2.7121 3.1094
2272 350 298.1225 293.8553 305.0185 2.3923 1.8723


Evgeniy Shkondin, DTU Nanolab, 2020.

X-ray photoelectron spectroscopy

XPS measurements of all samples has been performed using XPS K-Alpha equipment. The purpose of the investigation is to get idea about film stoichiometry and possible contamination.

Stoichiometry

Stoichiometry results for AlN deposited with TMA and NH3 plasma
Number of cycles 568 852 1136 1704 2272
Average thickness (nm) 66.18 103.83 128.13 203.66 298.12
Al (at.%) 47.54 48.15 47.82 47.77 47.61
N (at.%) 40.80 40.60 41.13 41.01 41.11
O (at.%) 11.66 11.25 11.05 11.22 11.28

Presence of Oxygen and Carbon

Traces of carbon is found in the deposited films, their origine is not clear, but most likely due to TMA decomposition. Another source is incomplete ALD reaction. Oxygen is present in the film (up to 11 at.%)

  • C1s signal
    C1s signal
  • O1s signal
    O1s signal
  • C1s signal
    C1s signal
  • O1s signal
    O1s signal

Evgeniy Shkondin, DTU Nanolab, 2020.

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