Chapter 1 Textured and heteroepitaxial CVD diamond films

Abstract

In this chapter the advances in diamond heteroepitaxy and in textured diamond growth is reviewed and the problems, which remain to be resolved, are discussed. Significant progress in heteroepitaxial diamond growth has been achieved during the past few years. The synthesis of single crystalline diamond films and their applications as high temperature electronic materials still remain a great challenge for materials scientists. The crucial point preventing single crystal diamond growth is the observed crystallographic orientation deviation of individual diamond grains with respect to substrate and the resulting small-angle grain boundaries. Reduction of the average misorientation angle between grains in (001)- oriented chemical vapor deposition diamond films has been experimentally achieved by employing special modes of crystal growth. It is found that diamond grains with a very small misorientation angle of about 2° can coalesce to form a larger diamond grain by terminating the small-angle grain boundary between the grains by a disclination. It is furthermore demonstrated that the presence of boron in the gas phase during film deposition favors a step-flow lateral growth mode. This leads to overgrowth of the diamond grains of relatively large misorientation by the highly oriented neighboring grains.