Trace impurities measurements from LDetek ensure quality of synthetic diamonds ‘grown’ in the lab

Trace impurity detection expert, LDetek, has developed a complete turnkey solution for the production of synthetic diamonds. Using the combination of gas chromatograph with integrated flow selection and gas dilution , operators can accelerate the process of growing high quality cultured diamonds by chemical vapor deposition.

Large-scale synthetic diamond production uses the high-pressure, high-temperature (HPHT) process because it is the most economical method for producing large quantities of synthetic diamonds. However, the chemical vapor deposition (CVD) method produces the highest quality synthetic diamond possible in a relatively short time.

CVD creates a plasma of carbon above a substrate on which carbon atoms deposit to form diamond. It allows better control of the characteristics and properties of the diamonds but requires good control of the impurities in the hydrocarbon gases used, and this is where LDetek's trace impurity system plays a vital role.

N2 levels should be carefully checked, along with traces of O2 and H2O to confirm the purity of hydrogen, methane and other additive gases.

N2 traces from sub ppb to a few hundred ppm are measured with the LDetek PlasmaDetek2 detector mounted in the MultiDetek2 gas chromatograph. Optional H2O-NH3 and O2 analysis can be added in the same instrument when the process requires it. LDetek's LDGSS flow selection system provides the automatic switching sequence for analysis between H2/CH4 and the various additive gases, while the LDGDSA automatic dilution system can be added to accurately calibrate gases in parts per billion.

Synthetic diamonds - also called cultured diamonds - are created around the world and used in the same way as naturally occurring diamonds. This includes jewelry, electronics, cutting machines and tools, thermal conductors and optical materials. For the industry, synthetic diamonds are less expensive, but they are considered a highly ethical product, since their production has little humanitarian or environmental impact. For jewelry, other benefits are the ability to produce shapes not possible in nature and better quality control of the stones.

The complete and detailed application note, which includes information on lower detection limits and chromatograms of measurements, is available for download at ProcessSensing.com:
Measurement of Trace Impurities for Synthetic Diamond Grown by Chemical Vapor Deposition (CVD)