Micro-scale abrasion investigations of single-crystal diamond wafer

Single-crystal diamonds are widely used as cutting tools and wear-resistant tools. For such applications, natural type Ia diamonds or high-pressure and high-temperature (HPHT) synthetic type Ib diamonds are primarily used. In these single-crystal diamonds, the content and distribution of nitrogen impurities and crystal defects greatly vary depending on the crystal. In particular, natural diamonds have very different amounts of impurities, aggregated states, or structural defects

depending on the locations in the crystals, reflecting the complex thermal history of growth inside the Earth. On the other hand, HPHT synthetic diamonds are grown under certain stable pressure and temperature conditions and therefore do not have such large variations in quality. However, the concentration of substitutional nitrogen inpurities varies depending on the growth sectors, which causes different

abrasion resistance depending on the locations in the crystals. Therefore, when applying these natural or synthetic single-crystal diamonds to precision cutting tools and wear-resistant tools, it is very important to appropriately evaluate the abrasive properties in minute regions in the crystal. Various methods for conducting micro-scale abrasion tests for single-crystal diamonds have been attempted, such as using small diameter (25–50 mm) cas iron wheel (with fine diamond powder provided) or a metal-bonded diamond grindstone wheel. However, since the wheel material is much softer than single-crystal diamonds, the cutting edge of the wheel deteriorates quickly, which makes it difficult to accurately evaluate abrasive properties in practice.

Nano-polycrystalline diamond (NPD) produced by the direct conversion sintering method under ultra-high pressure has higher hardness and abrasion resistance than single-crystal diamond. Therefore, it is used as a cutting tool for the precision machining of cemented carbide and hard ceramics. According to the results of macro-scale abrasion tests by sliding the entire surface of the sample, the abrasion

resistance of NPD is much higher than that of the (001)〈100〉 plane directions of single-crystal diamond and at a level equal to or higher than the high abrasion-resistant surface directions such as (001)〈110〉plane-directions. Therefore, it is considered that grinding wheels manufactured from NPD can appropriately evaluate the abrasive properties

of single-crystal diamonds. By reducing the diameter of this NPD wheel to a millimeter level, it is possible to evaluate abrasive properties in a smaller area of several tens of μm. Here, we report experiments to verify the micro-scale abrasion test method using this NPD wheel and also some test results on various single-crystal diamonds by this method.

CSMH, a wide bandgap Semiconductor Material and Device company manufacturing with unique technology with investments from Korea, China, and Singapore. we are equipped with advanced semiconductor production equipment to produce high-quality Diamond wafers and AlN templates on a variety of substrates, including Si, sapphire, and polished diamond wafer.

The company has built an intelligent manufacturing plant, started mass production of diamond wafer, diamond heat sinks, and has a substantial intellectual property (IP) portfolio. Our product's performance has improved to a level that is among the best in the world after more than 10 years of technological development.