# Quartz tube chemical vapor deposition reactor

This wiki details the construction of a 2 kW NIRIM type MWCVD (microwave chemical vapour deposition) reactor at the Cardiff Diamond Foundry suitable for diamond deposition on up to 1 inch substrates. The CAD file, schematics, and images detailing the construction of the reactor as well as the LabVIEW VI (virtual instruments) to interface with the attached hardware are all free to use and modify. It is hoped that the authors will be acknowledged should the information within this wiki be of use and informed of any improvements made to the design.
All microwave components are supplied by Sairem, with the product codes below, while the vacuum chamber is composed of a quartz tube and largely ‘off the shelf’ KF fittings. To seal the quartz tube 2 trapped O-rings are compressed uniformly at each end with the sample positioned within the plasma through the use of a dielectric quartz rod and ceramic sample holder. Sample loading and repeatable placement within the plasma is then facilitated through sliding the central quartz rod along a pair of guide rails fixed between the top and bottom plates of the table structure. To reduce the footprint and support structure of the reactor the magnetron is placed underneath the vacuum chamber through the use of two E-bend waveguides while its power supply is attached vertically to the side of the support structure.
The MKS flow controllers and Vacuubrand pump controller are interfaced through RS232/USB with a laptop and operated with the LabVIEW VI provided below. In addition, the VI are able to read temperature from a Williamson pyrometer and provides a series of software interlocks to prevent potentially dangerous oxygen/hydrogen mixtures and over pressurisation of the predominantly quartz chamber.
The following images as well as the .dwg and .vi files are available as one one .zip file.
UPDATE: An upgraded version of the design utilising CF flanges and solving some of the issues of the KF iteration has been created in collaboration with Evince Technology, with the .dwg files available as one .zip file.
To view the .dwg files without an AutoCAD licence the free to download DWG Trueview program can be obtained at http://www.autodesk.com/products/dwg/viewers, with further CAD formats available on request.
For further information on the design and operation of the reactor please refer to the article A simple, space constrained NIRIM type reactor for chemical vapour deposition of diamond or contact Prof. Oliver Williams at:
WilliamsO ( at Cardiff.ac.uk )
Further information on the work of the Cardiff Diamond Foundry can be obtained from:
http://www.nanodiamond.co.uk/Home.html
Sairem microwave components
* 3 stub tuner (Al3SMWR340D24X25MRR2PE-B)
* Quartz window (FQAWR340RVAL)
* Arc detection flange
* Downstream source (DOWNSTREAMWR340SPSA50C)
* Manual sliding short circuit (PCCMWR340L130PVMR1PE-B)
* 2 kW 2.45 GHz MW generator (GMP20KSM56M230FST3IR)
* 2 x E-bend waveguide (CDWR340E090AL080X080PE)
* 1 x 900 mm waveguide (TRONCON GUIDE WR340 - 900mm)
DISCLAIMER: While best attempts have been made to ensure the safety of the design and software written to operate the reactor laid out within this wiki, CVD is not free from risk. As such, with the use of the attached plans and software comes the agreement that the reader holds the authors and their institution free from liability for any injuries and financial costs that may result from their use. In addition, the authors strongly recommend that adequate interlocks and operating procedures are put into place to ensure the safe operation of any resulting CVD reactors.
* Magnetron and guide rails of NIRIM reactor. The guide rails to the left of the image are bolted to the top and bottom of the support structure and tensioned to allow the quartz rod and sample holder to be slid in and out of the vacuum chamber.
* Bottom of NIRIM reactor vacuum chamber. The guide rails to the left of the image facilitate the removal of the quartz rod and sample from the centre of the reactor, while the flexi hose is connected to a Vacuubrand membrane pump. The 'off the shelf' tee and KF fittings to the right provide flanges for a PRV, vent valve, and capacitive vacuum gauge.
* Top of NIRIM reactor vacuum chamber. The tee attached to the top of the quartz tube provides flanges for a baratron pressure interlock, gas inlet, and alignment gimble for a Williamson pyrometer.
* Manifold of NIRIM reactor. A series of MKS flow controllers are controlled by a LabVIEW VI with manually actuated pneumatic valves for safe operation.
* Front view of NIRIM reactor. Magnetron positioned underneath sample stage through the use of E-field bends and waveguide to minimise the footprint of the reactor.
* Rear view of the NIRIM reactor. To further save space the magnetron power supply is suspended vertically from the table.
* Overview schematic of NIRIM reactor.
* Schematic of NIRIM reactor chamber and sample holder.
* Cardiff Diamond Foundry NIRIM reactor virtual instrument.