Remote Epitaxy of 4H-SiC on Epitaxial Graphene/SiC

Remote epitaxy technique has the possibility of impacting many research areas including SiC and GaN SMART power, integration of opto- and electronic devices, HEMT performance, flexible electronics and quantum sciences. SiC, a wide band gap semiconductor, has attracted attention because of its various band gap depending on its polytype, superior thermal conductivity and chemical stability which enable SiC to outperform GaN for applications in extremely harsh operating conditions such as high temperature, aerospace, radioactive environment, etc. In addition, SiC recently has been used as a template for state-of-art such as topological insulator and color center for quantum applications. In spite of its usefulness, the expensive wafer cost of SiC has hindered its scalability and commercialization. Even though the remote epitaxy has proven that it can dramatically reduce wafer cost by reusing substrate, the remote epitaxy of SiC has not been demonstrated.<br/>In this work, we focus on the remote epitaxy of 4H-SiC, which is directly grown on epitaxial graphene (EG) on 4H-SiC (0001) substrate using a chemical vapor deposition (CVD) reactor. The epitaxial graphene was grown via Si sublimation of 4H-SiC substrate. Both on-axis (4H-SiC) and off-axis (4H-SiC cut 4° off-axis towards the [11-20]) substrates were investigated. Following the epitaxial graphene growth, SiC growth was performed. Growth parameters were modified to eliminate SiC polytype conversion and other extended defects and to preserve the graphene at elevated temperatures during the growth for successful remote epitaxy. The epitaxial SiC films were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD). To evaluate the ability to grow 4H-SiC remote-epitaxially, a Ni metal stressor technique was used to exfoliate the SiC epitaxial film and demonstrated exfoliation yields of up to 50 – 70 %.