ABSTRACT
Silicon on insulator (SOI) technology (more specifically, silicon on sapphire) was originally invented for the niche of radiation-hard circuits. In the last 20 years, a variety of SOI structures have been conceived with the aim of dielectrically separating, using a buried oxide (Fig. 4.1(b)), the active device volume from the silicon substrate.1 Indeed, in an MOS transistor, only the very top region (0.1-0.2 µm thick, i.e., less than 0.1% of the total thickness) of the silicon wafer is useful for electron transport and device operation, whereas the substrate is responsible for detrimental, parasitic effects (Fig. 4.1(a)).
