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Deposition of Silicon Nitride using PECVD

At the moment DTU Nanolab has 2 PECVDs that can deposit silicon nitride and silicon oxynitride. PECVD4 is for clean silicon based and III-V based samples. PECVD3 is for silicon based samples but here up 5% (4 cm2) wafer coverage of other materials as metals are allowed (under some conditions even more). Look at the PECVD page to learn more about the PECVDs at DTU Nanolab. All though PECVD3 and PECVD4 are very much alike you cannot count on the a recipe on one system will give exactly the same results on the other system.

Deposition of SiN with PECVD4

Quality Control (QC) for PECVD4

QC Recipe:	QCNITRIDE=HFSIN
SiH₄ flow	40 sccm
NH₃ flow	55 sccm
N₂ flow	1960 sccm
Pressure	900 mTorr
RF-power	HF: 20 W

QC limits	PECVD4
Deposition rate	11.0-13.2 nm/min
Non-uniformity	<3.0 %
Refractive Index	1.988 - 2.018

* Due to recent oscillations on the QC nitride recipe (HF), new tests were performed. Learn more about it under NEW TESTS QC . (Still under development.)

Recipe	Dep. rate [nm/min]	RI	Unif. [%]	Stress [MPa]	Comments	SiH4 [sccm]	NH3 [sccm]	N2 [sccm]	Pressure [mTorr]	Power [W]	Time [mm:ss]	Tested
MF SIN	12.9-13.0 nm/min 11.7 nm/min (kabi 2019-03-01)	2.038-2.044	± 1.7%	157 MPa	more results	40	40	1920	900 mTorr	20HF6"/20LF2"	10:00/60:00(stress)	February 2017 Berit Herstrøm @DTU Nanolab (bghe)
MF SIN2	44.3 nm/min	2.01-2.02	± 2.7%	? MPa		30	30	1470	850 mTorr	100HF8.2"/100LF2.2"	10:00	February 2020 bghe
LF SIN	40-43 nm/min	1.983-1.984	± 3.9-4.4%	Compressive: 565.4 MPa		40	20	1960	550 mTorr	60LF	2:00/23:00(stress)	February 2017 bghe
HF SiN	12.2-12.4 nm/min	2.017-2.021	± 1.2-1.6%	Tensile: 431.6 MPa		40	55	1960	900 mTorr	20 W	10:00/56:00(stress)	February 2017 bghe

Recipes on PECVD3 for deposition of silicon nitride

Quality Controle (QC) for PECVD3

QC Recipe:	QCNITRIDE
SiH₄ flow	30 sccm
NH₃ flow	30 sccm
N₂ flow	1470 sccm
Pressure	845 mTorr
RF-power	HF: 100 W 7.8s LF: 100 W 2.2s

QC limits	PECVD3
Deposition rate	~40 nm/min
Non-uniformity	<3.0 %
Refractive Index	2.02 - 2.04

Recipes

Recipe name	SiH4 flow [sccm]	NH3 flow [sccm]	N2 flow [sccm]	Pressure [mTorr]	Power [W]	Description
MFSiNLS2	30	30	1470	845	100HF 7.8s 100LF 2.2s	Low stress nitride - standard recipe. The latest measured values can be seen in the process control sheet in LabManager.
MFSiNLS	30	30	1470	650	20HF 6s 30LF 2s	Low stress nitride - old standard recipe. This one is not running well any more.
LFSiN	30	15	1470	550	60LF	Compressive stress
HFSiN	30	42	1470	900	20HF	Tensile stress

LF=Low Frequency HF=High Frequency MF=Mixed Frequency SiN=Silicon Nitride LS=Low Stress

Expected results

Recipe name	Deposition rate [Å/min]	RI	Uniformity [%] [Std./mean]	Stress [MPa]	KOH etch rate [Å/min]	BHF etch rate [Å/min]	See more
MFSiNLS2	~422 (bghe Feb 2016)	~2.03	~2	~6 (bghe Feb 2016)	~2.1 (bghe Feb 2016)	~?	see more results
MFSiNLS	~107	~1.99	~4	~-30	~2.5	~250	.
LFSiN	~550	~1.96	~3	~-630	.	.	.
HFSiN	~130	~1.97	~2	~460	.	.	.

Recipes on PECVD2 for Deposition of Silicon Nitride

Expired Recipes! The PECVD2 has been decomissioned and is no longer available.

Recipes

Recipe name	SiH4 flow [sccm]	NH3 flow [sccm]	N2 flow [sccm]	Pressure [mTorr]	Power [W]	Description
SINSTD80	30	20	1000	500	80
SINSTD96	30	20	1000	500	96
1SiN	40	20	1000	700	150

Expected results

Recipe name	Deposition rate [nm/min]	RI	Uniformity [%]	Stress [MPa]	BHF etch rate [Å/min]	Comments
1SiN	Deposition rate in the middle of two wafers: 49nm/min+-1nm/min (2015-04-24 BGHE) In the middel: 72.6-76.4 nm/min (2014-08-13 BGHE) Old shower head Variation over 3 wafers: 71.4-78.6 nm/min (2014-08-13 BGHE) Old shower head		~2-4% (2015-04-24 BGHE) ~5% in the middel (4") (2014-08-13 BGHE) Old shower head ~10% over 3 wafers (2014-08-13 BGHE) Old shower head
SINSTD80	68nm/min (2014-07-07 JML)- unstable deposition rate
SINSTD96 - unstable deposition rate

Recipes on PECVD1 for Deposition of Silicon Nitride

Expired Recipes! The PECVD1 has been decomissioned and is no longer available.

Recipes

Recipe name	SiH4 flow [sccm]	NH3 flow [sccm]	N2 flow [sccm]	Pressure [mTorr]	Power [W]	Description
1nitride	30	20	1000	500	80
1nit_std	40	20	1960	550	60	Process control recipe

Expected results

Recipe name	Deposition rate [nm/min]	RI	Uniformity [%]	Stress [MPa]	BHF etch rate [Å/min]	Comments
1nitride
1nit_std	~32	1.89	~1		~700	The latest measured values can be seen in the process control sheet in LabManager

Oxynitrides

The recipe for making oxynitrides will depend on what kind of oxynitride you need. If you need a little higher refractive index than SiO2 then start with an SiO2 recipe and then add NH3 until the right refractive index is obtained. If you need very high refractive index a little lower than for silicon nitride then it is probably better to start with a silicon nitride recipe and add a some N2O until you get the right refractive index.

We had a Ph.d student long time ago Klaus Bo Mogensen that did the first. You can find his ph.d. thesis here: Integration of Planar Waveguides for Optical Detection in Microfabricated Analytical Devices

Berit H. has the thesis in her office.