Specific Process Knowledge/Thin film deposition/ALD2 (PEALD)/AlN deposition using ALD2

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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 only run all nitride processes 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

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

Evgeniy Shkondin, DTU Nanolab, 2020.

Spectroscopic ellipsometry

Refractive index and permittivity

Thickness distribution and uniformity


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

Stoichiometry

Presence of Oxygen and Carbon

image:eves_20200609_AlN_NH3_XPS_3D_C1s.png| C1s signal image:eves_20200609_AlN_NH3_XPS_3D_O1s.png| O1s signal </gallery>