ABSTRACT
The synthesis of diamond has been a dream of mankind since the 19th century when it was discovered that diamond is an allotrope of carbon. It was from this time that scientists eagerly tried to find an approach for conversion of the stable form graphite into the metastable form diamond. The first successful approach in 1953 was based on duplicating nature’s method using conditions that are similar to a great depth within earth, typically pressures of several gigapascals and temperatures in excess of 1,200°C. The so-called high-pressure high-temperature (HPHT) method is well employed in today’s synthetic diamond industry, producing hundreds of tons each year. Today, even a com mercial production of high-quality gemlike stones of more than 3 carats is realized (e.g., Scio Diamond Technology Corporation or Brilliant Earth). However, due to its restriction in shape and size and infeasibility for integration into common microfabrication processes, the use of HPHT is mainly
found in mechanical abrasion applications such as cutting, grinding, and polishing. A much more versatile method for synthesizing diamond using a low-pressure chemical vapor deposition (CVD) technique was developed by different groups between 1962 and 1970 [1-3]. From that time on, this tech nique made it feasible to coat a variety of materials with diamond. In contrast to the HPHT method, yielding only single crystalline diamond stones, typical CVD diamonds consist of numerous small crystallites forming a continuous film. These polycrystalline diamond films can reach bulk properties similar to those of natural diamond. This chapter gives an overview of the diamond deposition process, including the substrate pretreatment to enhance diamond formation, the basic principles of diamond growth, and the two most used techniques. A survey of the most important growth para meters and their influence on diamond’s micro structure closes the chapter.
