| This dissertation describes a semiconductor layer transfer process using wafer bonding and hydrogen-induced semiconductor cleavage. In this process, hydrogen is implanted into a wafer that has the layer to be transferred. The implanted hydrogen ions form a highly damaged region around the hydrogen stopping range. The implanted wafer is then bonded to another wafer using low-temperature direct bonding. With appropriate heat or mechanical treatment, the bonded wafer pair separates along the highly damaged region, resulting in the transfer of the layer from one substrate to the other.; With this technique, we have been able to fabricate silicon-on-insulator (SOI) structures by transferring single- and poly-crystalline silicon layers, especially using hydrogen plasma implantation, oxygen plasma-activated wafer bonding, and thermal cleavage and mechanical cleavage methods. We have also formed silicon, SOI, and oxide membranes on buried cavities and channels, which can be applied for use in pressure transducers, micro-fluidic systems, and radio frequency filters and resonators. In these demonstrations, we have observed good thickness uniformity (<1%) across a 100 mm wafer and surface microroughness (<10 nm) of the transferred layers.; For the transfer of pre-fabricated electronic device layers, gate oxide damage was first evaluated after high-dose and high-energy hydrogen implantation through metal-oxide-silicon (MOS) transistors. The results showed that stress-induced leakage current (SILO) through the gate oxide increased as hydrogen dose increased for the 5 nm-thick oxide. For the 1.8 nm-thick gate oxide, no SILC was observed, showing that the implantation damage is not significant for the ultra-thin (<2 nm) oxides.; To protect the thicker (>3 nm) oxides from damage during the hydrogen implantation, we have proposed layer transfer with patterned implantation of hydrogen. In this process, active device regions were masked during the implantation. This experiment showed that the hydrogen induced silicon layer cleavage is feasible even without a continuous hydrogen implantation of the entire wafer, and that the silicon cleavage can propagate across at least 16 microns of non-implanted area from a 4 micron-wide implanted region each side. Furthermore, it has shown that the mechanical cleaving can overcome some non-implantation area limitations imposed by the thermal cleavage process. |
