Microwave Plasma Chemical Vapour Deposition (CVD) Equipment: A Journey to Diamonds in the Gas State

Microwave Plasma Chemical Vapour Deposition (MPCVD) equipment takes a very different approach to growing diamonds than HPHT. What are the key points that we need to pay attention to when using MPCVD equipment to cultivate diamonds?

1. Reaction Gas Supply System

The MPCVD machine requires a reaction gas supply system. This system supplies carbonaceous gases such as methane (CH₄) and reaction gases such as hydrogen (H₂). These gases act as the ‘raw material pool’ for building diamonds. Methane provides the carbon atoms, while hydrogen aids and stabilises the reaction. Experts emphasise that the purity of the gases is critical, as high purity reaction gases help to improve the quality of the diamonds being grown. If the gas contains impurities, they may be mixed into the crystal structure of the diamond and affect its quality.

2. Reaction Chamber

The reaction chamber is the core part of the MPCVD equipment. After the reaction gas is introduced into the reaction chamber, the decomposition reaction occurs under the action of energy sources such as microwave, radio frequency or hot wire. Taking microwave MPCVD equipment as an example, the microwave energy causes the gas molecules in the reaction chamber to be excited, and the carbon atoms in the methane are released, and then gradually deposited on the substrate, layer by layer, to grow a diamond film or crystal. Parameters such as pressure, temperature and airflow conditions inside the reaction chamber need to be precisely controlled. For example, the pressure is generally maintained at a low level, usually between tens and hundreds of Pascals, which aids in the diffusion of gas molecules and the homogeneity of the reaction.

3. Substrate materials

Substrate material also plays an important role in the MPCVD diamond cultivation process. It is where carbon atoms are deposited, just like the foundation of a house. Commonly used substrate materials include silicon chips and so on. The choice of substrate material affects the direction and quality of diamond crystal growth. Different substrate materials have different bonding characteristics with carbon atoms, which requires the selection of the appropriate substrate material according to the actual needs.

Whether it is high-temperature and high-pressure equipment or chemical vapour deposition equipment, they all play an irreplaceable role in the process of cultivating diamonds. With the continuous development of science and technology, these equipments are also being improved and optimised, which makes the quality of cultivated diamonds higher and higher, and the production capacity larger and larger. This not only meets the growing market demand for cultivated diamonds, but also allows more people to enjoy the sparkling beauty of diamonds.

These diamond cultivation facilities are like the magic wand of modern technology, transforming carbon atoms into breathtaking diamonds and opening up a new era in diamond manufacturing.