Specific Process Knowledge/Thin film deposition/PECVD

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PECVD Plasma Enhanced Chemical Vapor Deposition

Name PECVD4: PRO CVD
Vendor: SPTS

PECVD3 - positioned in cleanroom A-1, photo: DTU Nanolab internal

PECVD4 - positioned in cleanroom B-1, photo: DTU Nanolab internal

We have two PECVD's here at DTU Nanolab. They can both be used to deposit Silicon oxides and Silicon nitrides with or without dopants of Boron and Phosphorus. PECVD3 can also deposit thin layer of aSi. PECVD3 is used for silicon based processing with small amounts (<5% wafer coverage, under some condition even more) of metals where as PECVD4 is dedicated for clean wafers both for silicon based materials and III-V materials. Quartz carriers are used in PECVD4 and they are dedicated the two different material groups to avoid cross contamination. See the precise rules in the equipment manuals which are uploaded in LabManager.

PECVD is a chemical vapor deposition process that applies a plasma to enhance chemical reaction rates of reactive species. PECVD processing allows deposition at lower temperatures, which is often critical in the manufacture of semiconductors. PECVD films are however known for not being stochiometeric and normally a lot of hydrogen is incorporated inside the films.

All though PECVD4 and 3 are very similar you should not expect to transfer a recipe between the systems and get the exact same result.

The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager (requires login):

PECVD3 in LabManager
PECVD4 in LabManager

Process information on PECVD3 and PECVD4

• Recipes for deposition of silicon oxides
• Recipes on for deposition of silicon nitride and silicon oxynitride
• Doping with boron
• Pre-release tests on PECVD4

• Si deposition using PECVD3

Overview of the performance of PECVD thin films and some process related parameters

PECVD		PECVD3	PECVD4
Purpose	Deposition of dielectrica	Silicon oxide Silicon nitride Silicon oxynitride BPSG (Boron Phosphorous doped Silica Glass) aSi	Silicon oxide Silicon nitride Silicon oxynitride BPSG (Boron Phosphorous doped Silica Glass)
Performance	Film thickness	~10nm - 30µm	~10nm - 30µm
	Index of refraction	~1.4-2.1	~1.4-2.1
	Step coverage	In general: Not so good BPSG: Floats at 1000oC	In general: Not so good BPSG: Floats at 1000oC
	Film quality	Not so dense film Hydrogen will be incorporated in the films	Not so dense film Hydrogen will be incorporated in the films
Process parameter range	Process Temperature	300 oC	300 oC
	Process pressure	~200-900 mTorr	~200-900 mTorr
	Gas flows	SiH4:0-60 sccm N2O:0-3000 sccm NH3:0-1000 sccm N2:0-3000 sccm GeH4:0-6.00 sccm 5%PH3:0-60 sccm 3%B2H6:0-1000 sccm	SiH4:0-60 sccm N2O:0-3000 sccm NH3:0-400 sccm N2:0-3000 sccm Ar:0-1000 sccm He: 200sccm 5%PH3:0-100 sccm 3%B2H6:0-850 sccm
Substrates	Batch size	One 4" wafer per run One 6" wafer per run Or several smaller pieces on carrier wafer Deposition on one side of the substrate	One to 7 2" wafer per run One 4" wafer per run One 6" wafer per run Or several smaller pieces Deposition on one side of the substrate
	Materials allowed	Silicon wafers, Quarts (fused silica) wafers with layers of silicon oxide or silicon (oxy)nitride Other material (can be allowed if less than 3.9 cm2 is exposed to the plasma (<5% coverage of a 4" wafer), please ask!	Silicon wafers, Quartz (fused silica) wafers, with layers of silicon oxide or silicon (oxy)nitride III-V wafers (on special carriers)