Chapter 2 - Silicon carbon nitride: A new wideband gap material

Abstract

This chapter discusses a new wideband gap materia— silicon carbon nitride (SiCN). It traces the growth and characterization of this new material. Microwave Chemical Vapor Deposition (MW-CVD), Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD), as well as ion beam sputtering and magnetron sputtering techniques have been employed to synthesize CNx and SiCxNy materials. Depending on the specific process conditions, amorphous and crystalline phases with a wide range of composition as well as a variety of microstructures and morphologies, including highly oriented films, nanorods, and nanocrystalline films can be formed. Silicon (Si) incorporation was crucial for crystal growth by CVD methods, whereas excessive Si addition in the Physical Vapor Deposition (PVD) process induced amorphization of the nanocrystalline SiCxNy materials. CNx and SiCxNy exhibited optical properties for wideband gap materials. Dependence on the composition of the optical properties was observed in this chapter. The band gap of c-SiCxNy can be varied between 3.8 to 4.7 eV, depending on the carbon mole fraction. Whereas CNx films gave a lower refractive index than diamond-like carbon (DLC) film. Incorporation of Si caused increases in the refractive index. Hence, the CNx system with Si addition enables a wide range of accessible optical constants for practical applications.