Thick Semi-Insulating 4H-SiC Layer Exfoliation for Non-Epitaxial Engineered Substrates

The growing demand for 4H-SiC substrates in power device fabrication has encouraged the development of engineered substrates to reduce costs and facilitate wafer re-usability for effective material utilization. This work presents a novel approach for manufacturing SiC power devices is to exfoliate the required drift layer thickness from ultra-high-quality Semi Insulating (SI) 4H-SiC material, bond it to a conductive SiC substrate and thus obtain the non-epitaxial engineered substrate. Energy-filtered Ion Implantation (EFII) technology enables custom doping profiles, precise control of doping concentration, and potentially robust material properties compared to as-grown epitaxial layers in the bonded layer. Key steps to exfoliate a 4μm thick SiC layer from semi-insulating substrates and bond it to low-cost, highly conductive mono-crystalline SiC are demonstrated. This paper mainly focuses on the physical characterization of demonstrated samples.