Specific Process Knowledge/Thin film deposition/DiamondCVD

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SEKI Diamond CVD - this machine is not in active use (2023)

On the left is a tall instrument rack with various panels and control screens. It says "Seki technotron" on top. There are indicator lamps and an EMO button. On the right is the processing chamber which is relatively small, it's a cylindrical vacuum chamber with a small window facing the viewer. It's connected to gas lines and an exhaust system on top. There's a large panel covering the lower part of the instrument.
The SEKI diamond CVD in cleanroom B-1

The SEKI AX5250S is a Microwave Plasma Chemical Vapor Deposition (MPCVD) system for growth of diamond thin films. The system is fitted with hydrogen, methane, and oxygen for diamond growth. Notice that this machine is rather manual and we don't have a stable process running on it. It would require a significant of work to develop a reliable process for depositing good-quality diamond for different applications. Therefore the machine will probably be decommissioned, though you are welcome to contact the Thin Film group if you are interested in using it as it is still in the cleanroom as of Jan 2024.

Depending on the starting material both polycrystalline and single crystalline diamond can be grown. Diamond has a lattice constant of 3.567 Å, which is not easily matched to other materials, and therefore in general diamond growth must be seeded by diamond as nucleation sites.

For single crystalline diamond this means that diamond layers in most cases must be grown on top of single crystal diamonds. For polycrystalline diamond, almost any material will do as long as it can withstand a growth temperature of 800 °C. It just needs to be seeded with nano diamonds. The seeding can happen by immersion into solution, by polishing, or by spray coating with nano diamonds.

The user manual, APV, technical information, and contact information can be found in LabManager:

Diamond CVD in LabManager


More details

Equipment performance and process related parameters

Equipment SEKI AX5250S
Purpose Diamond growth
  • Single crystalline diamond
  • Poly crystalline diamond
Parameters

H2

Up to 1000 sccm

CH4

Up to 50 sccm

O2

Up to 20 sccm (may be reduced, check)

Operating pressure

Max. >200 Torr (usually about 120 Torr for diamond growth)

Power

Up to 5000 W

Temperature

700-900 °C

Process Growth rate

About 8 Å/s (3 μm/hr)

Max thickness

About 100 μm

Uniformity

OK up to 50 mm diameter
1 μm thickness needed to ensure substrate coverage

Substrates Substrate size

up to 100 mm wafers, 50 mm preferred

Allowed materials

Ask


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