To improve thermal dissipation in silicon-on-insulator metal-oxide-semiconductor field-effect transistors (SOI MOSFETs), we recently proposed replacing the buried oxide with buried alumina, which offers higher thermal conductivity. However, because alumina is a high-k insulator, there is also a definite impact on the electrical properties, namely, coupling and short-channel effects. Our simulations show that the role of fringing fields is accentuated, leading to more severe drain-induced barrier lowering (DIBL)-like problems. The trade-off between the thermal merit and the electrical performance of very advanced SOI transistors is examined by comparing various MOS architectures. We conclude on the usefulness of a ground plane located underneath a relatively thin buried alumina. (C) 2004 The Electrochemical Society.