Growth Dynamics of Epitaxial Gallium Nitride Films Grown on c-Sapphire Substrates

Abstract

In the present scenario, semiconducting material based devices with new capabilities are redefining the existing technologies. The developments in III-Nitride thin-film technology have produced significant advances in high-performance optoelectronic and photovoltaic devices. However, the quality of the material is an important factor for the fabrication of nitride-based efficient devices. For instance, a large difference in the covalent bond radius of Gallium and Nitrogen atoms results in high dislocation densities in the III-Nitride compound, Gallium Nitride (GaN) which is sturdily ruled by residual strain in the GaN films. Another main source of residual strain is the lack of an appropriate lattice-matched substrate that will critically impact the optoelectrical performance of the fabricated devices. So, this chapter illuminates the solution to key challenges and elaborate on various parameters to grow GaN by using plasma-assisted molecular beam epitaxy (PAMBE) technique. Numerous efforts have been made for improving the quality of GaN semiconductor for high performance of device operation. This chapter elucidates the role of the growth variables towards high-quality epitaxial GaN films and discusses the stress-relaxation controlled defect minimization in detail. Also, it provides an in-depth understanding towards structural and interface quality of multilayered GaN/AlN heterostructure grown on c-plane sapphire substrate. Therefore, this chapter contributes distinctly to understanding the growth dynamics in GaN films and subsequently in GaN/AlN based multilayered heterostructures for next-generation promising nitride-based devices.