Specific Process Knowledge/Thin film deposition/PECVD

PECVD Plasma Enhanced Chemical Vapor Deposition

PECVD1 (part of cluster1) - positioned in cleanroom2

PECVD3 - positioned in cleanroom1

We have two (three) PECVD's here at DANCHIP. They can all be used to deposit Silicon oxides and Silicon nitrides with or without dopants of Boron, Phosphorus and Germanium. PECVD1 has been decommissioned and PECVD3 are used for silicon based processing with small amounts (<5% wafer coverage) of metals where as PECVD2 is dedicated for clean wafers both for silicon based materials and III-V materials. Quartz carriers are used in PECVD2 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 spices. PECVD processing allows deposition at lower temperatures, which is often critical in the manufacture of semiconductors.

All though PECVD2 and 3 are very similar you should not expect to transfer a recipe between the systems and get the exact same result.

Recipes on PECVD1(will be removed soon), PECVD2 and PECVD3

• Recipes for PECVD2 are in the III-V entry in LAbAdviser, see here
• Recipes on PECVD1 for deposition of silicon oxides
• Recipes on PECVD1 for deposition of silicon nitride and silicon oxynitride
• Recipes on PECVD3 for deposition of silicon oxides
• Recipes on PECVD3 for deposition of silicon nitride and silicon oxynitride

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

Purpose	Deposition of dielectrica	Silicon oxide Silicon nitride Silicon oxynitride PBSG (Phosphorous Boron doped Silica Glass) Silicon oxide doped with Germanium
Performance	Film thickness	~10nm - 30µm
	Index of refraction	~1.4-2.1
	Step coverage	In general: Not so good PBSG: Floats at 1000oC
	Film quality	Not so dense film Hydrogen will be incorporated in the films
Process parameter range	Process Temperature	300 oC
	Process pressure	~200-900 mTorr
	Gas flows	SiH$_{4}$:0-60 sccm N$_{2}$O:0-3000 sccm NH$_{3}$:0-1000 sccm N$_{2}$:0-3000 sccm GeH$_{4}$:0-6.00 sccm 5%PH$_{3}$:0-99 sccm 5%B$_{2}$H$_{6}$:0-1000 sccm
Substrates	Batch size	1-3 4" wafer per run 1 6" wafer per run Or several smaler pieces Deposition on one side of the substrate
	Substrate material allowed	Silicon wafers with layers of silicon oxide or silicon (oxy)nitride Quartz wafers
	Material allowed on the substrate	Aluminium All metals < 5% of the substrate coverage (ONLY PECVD3!)