Specific Process Knowledge/Thin film deposition/Deposition of Silicon Oxide/IBSD of SiO2

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Acceptance test for SiO2 deposition (2011) on IBE/IBSD Ionfab 300+)

.	Acceptance Criteria	Acceptance Result 1	Acceptance Result 2
Substrate information	50 mm SSP Si wafer 525 µm thick Supplied by Nanolab	100 mm SSP Si wafer 525+-25 µm thick	100 mm SSP Si wafer 525+-25 µm thick
Material to be deposited	SiO2 The purpose of the SiO2 is to be part of a mirror: <br\> 5 quarter wavelength pairs of <br\> SiO2 <br\> TiO2 <br\> Extra quarter wavelength layer of <br\> TiO2 <br\> 5 quarter wavelength pairs of <br\> SiO2 <br\> TiO2 <br\> Design wavelength (for refractive indices and layer thicknesses): 1300nm <br\> The acceptance criteria is set up for the single SiO2 and TiO2 layers. <br\> Five runs in a row for each material.	SiO2	SiO2
Deposition thickness	222 nm	~215 nm	224nm
Deposition rate	6 nm/min	7.42 nm/min +- 0.04nm/min One standard deviation	7.73 nm/min Only made once
Thickness uniformity	<+-1%	+-(0.46% +-0.10%)	+-0.45%
Reproducibility	<+-1.5%	+-0.6%	Not measured
Stress	<500 MPa	~600 MPa	475 MPa
Refractive index	.	1.490+-0.004 (stddev wafer to wafer)	1.482+-0.002 (stddev on wafer)

	Recipe 1	Recipe 2
Platen angle	15 degrees	10 degrees
Platen rotation speed	20 rpm	20 rpm
Ar(N) flow	4 sccm	4 sccm
Ar(dep. source) flow	9 sccm	8 sccm
I(N)	310 mA	320 mA
Power	675 W	700 W
I(B)	310 mA	280 mA
V(B)	1200 V	1100 V
Vacc(B)	400 V	400 V
Deposition time	29 min	37 min

Other results

Roughness of the surface

Measured with the Optical profiler - PSI mode (on one sample from the acceptance test): Sa= 0.6 nm

Uniformity and break down voltage by Mathias Engholm 2016-11-29

Mathias made 105.62nm SiO2 on a test silicon wafer and on his sample wafer. The sample wafer had gold/Cr on the surface and that had to be electrically isolated. The uniformity over the wafer of the oxide was 0.19% over 9 points - this is better than he has achieved when oxidizing in a furnace. He anodic bonded the wafer without problems. He measured the breakdown voltage and got 0.82+/+ 0.13 V/nm over 24 points. This is just as good as the oxide from the furnaces. Before his deposition he ran a 20 min heat up and 40min dummy deposition to clean the target. This was done with a bright new target and with the small deposition grids mounted.

Breakdown voltage over the wafer, by Mathias Engholm 2016-11-29

Thickness uniformity over the wafer, by Mathias Engholm 2016-11-29