High-Quality SiC Remote Epitaxy for Stackable Electronics

Remote epitaxy (RE) is a growth process performed on a graphene-covered substrate where the adatom registry is guided by the electrostatic fields penetrating through the graphene from the underlying substrate rather than interactions with the graphene lattice. The remote epitaxy is easily exfoliated from the substrate due to weak van der Waals bonding of the graphene to the substrate, enabling transfer to desired substrates and thus allowing heterostructures that typically cannot be created with current methods. This technique has the possibility of impacting several research areas including SiC and GaN SMART power, integration of opto- and electronic devices, improving HEMT performance by transferring to higher thermal conductivity substrate, flexible electronics and quantum sciences.<br/><br/> In this work, we focus on the RE of SiC grown on graphene on SiC (0001) using a hot-wall chemical vapor deposition reactor. Controlling the thickness of graphene is achieved using off-axis substrates, where 1 – 5 monolayers is possible. To maintain the graphene during SiC remote epitaxy, a study of the Ar/H₂ flow ratio during remote epitaxial growth was conducted. Single crystalline material was achieved for both the on- and off-axis substrates when a low C/Si ratio was used. This growth condition resulted in a stepped film morphology for the on-axis substrate while the off-axis substrate produced intermittent step bunching, consistent with typical off-axis growth at low C/Si ratios. Films were characterized using Nomarski microscopy, scanning electron microscopy, transmission electron microscopy and electron backscattering detection. In summary, the growth of high quality SiC RE is shown to result from both on- and off-axis SiC substrates and has the possibility to be used for power electronics and quantum sciences applications.<br/> <br/>Research at NRL was supported by the Office of Naval Research.