ULTRA-NEAR-SURFACE GALLIUM-ACTIVATED 435NM LUMINESCENCE FROM DONOR-ACCEPTOR-PAIR RECOMBINATION IN ION-BEAM IMPLANTED 4H SIC

Abstract

Silicon carbide is the first material to exhibit electroluminescent characteristics and was used in the LED industry due to its ability to emit blue light. Although alternative materials have been developed to address the lower emission efficiency and challenging manufacturing conditions of SiC, the recent demand for rare-earth free phosphor materials has revived interest in DAP SiC as a potential candidate for LED applications. Its high quantum efficiency, better color rendering, sustainability, and cost advantages make it a promising option. A general introduction to SiC material properties is given in Chapter 1, including developments of SiC crystal growth, luminescence applications and the mechanism of donor-acceptor recombination. Chapter 3 elaborates on the experiments and characterization methodologies used. A brief description of each method, along with a detailed discussion of their advantages and the reason for selection, will be provided. In this thesis, gallium and nitrogen co-doped 4H-SiC luminescence is achieved through the ion implanting of highly spatially resolved Ga patterns into n-type SiC with the assistance of an ion milling tool. A [0002] oriented AlN thin film is manufactured by using sputtering techniques, and the influence of sputtering parameters on crystal orientation is discussed in Chapter 4. The AlN encapsulation layer serves to protect and passivate the SiC and nano-scale ion implantation regions under extreme annealing conditions. Chapter 5 presents and analyzes the experimental results, including photoluminescence (PL) and cathodoluminescence (CL), to identify the emission characteristics of the material and the associated defect energy levels. Surface characteristics of both SiC and AlN thin films are determined using SEM, TEM, and Raman spectroscopy. The morphological evolution of SiC cross-sections annealed at different temperatures is discussed in Chapter 6. Finally, Chapters 7 and 8 cover the conclusions and prospects of the project.