Evolution of defects, morphologies and fundamental growth characteristics of CVD diamond films induced by nitrogen addition

Abstract

Diamond is a very promising material with exceptional properties for many high value-added applications especially due to the incorporation of impurities. As one of the most important impurities, nitrogen is widely found in natural and synthetic diamonds, and the control of nitrogen-related defects in diamond is definitely at the spotlight for its potentials in room temperature quantum applications. Since chemical vapor deposition (CVD) is one of the most promising techniques for diamond doping and realization of defect control, it is thus crucial to investigate the nitrogen impurities in as-grown CVD diamond. In this work, single-crystal diamonds were grown with different nitrogen concentration and the evolution of defects, morphologies and fundamental growth characteristics of the CVD diamond films was explored by various modern analysis and detection methods. It could be concluded that the introduction of nitrogen could result in an evident increase in supersaturation of the growth radicals at the growth interface, which would eventually distinctly promote the (100)-oriented diamond growth. In consequence, single-crystal diamonds of high crystalline quality and few carbonaceous impurities could be achieved at high growth rates with appropriate amounts of nitrogen addition. As the nitrogen concentration increased, the structure and content of the defects would evolve as well with the domination of point defects, probably leading to lattice deformation in the as-grown diamond films. The surface morphologies of the nitrogen-doped CVD diamond films could also be distinctly altered with the compromise between the development of step bunching process and the occurrence of two-dimensional growth, which would eventually lead to variations of the surface roughness and uniformity of the as-grown diamond films.