Controlled-spalling of thin layers from 4H-silicon carbide substrates for biomedical applications

Abstract

The following thesis presents and discusses a novel approach in creating thin monocrystalline layers out of 4H silicon carbide (4H-SiC) for biomedical applications. Porosifying the surface of a single crystalline silicon carbide (4H-SiC) wafer with means of metal assisted photo chemical etching (MAPCE) promotes the adhesion of an electroplated nickel (Ni) layer. By utilizing a mechanical peel-off process, a Ni layer with tailored mechanical stress is first deposited and then peeled off such that also a thin layer of 4H-SiC is detached from the substrate. To create optimal peeling conditions, calculations are conducted to find appropriate parameters for a successful spalling process. The created sheet of SiC is characterised in a scanning electron microscope (SEM) to analyse its quality in regard of homogeneity, and thickness. These thin and flexible layers are especially important for creating electronics for biomedical applications as they can bend and stretch in the desired environment without comprising on its functionality and reliability for different applications like in-vivo drug delivery or as a robust electrode.