Novel device architectures and materials are required to extend the limits of ULSI microelectronics. Recent properties of UNIBOND(R) and SOS substrates, determined with the pseudo-MOSFET technique are described. The discussion of advanced SOI devices includes two basic aspects: the scaling of conventional MOSFETs and the design of alternative structures. We discuss the effects resulting from the reduction in channel width, length and thickness and present the merits of more innovative transistors with ground-plane, dynamic-threshold or double-gate.