Sign reversal of the Hall resistance in the mixed-state of La1.89_{1.89} Ce0.11_{0.11}CuO4_{4} and La1.89_{1.89}Ce0.11_{0.11}(Cu0.99_{0.99}Co0.01_{0.01})O4_{4} thin films

The transport properties of La$_{1.89}$Ce$_{0.11}$CuO$_{4}$(LCCO) and La$_{1.89}$Ce$_{0.11}$(Cu$_{0.99}$Co$_{0.01}$)O$_{4}$ (LCCO:Co) superconducting thin films are investigated. When the external field $\bf H$ is applied along the crystallographic c-axis, a double sign reversal of the Hall voltage in the mixed state of LCCO:Co thin films is observed whereas a single sign reversal is detected in LCCO. A double sign reversal of the Hall signal in LCCO can be recovered if the magnetic field is tilted away from the plane of the film. We find that the transition from one to two of the Hall sign reversal coincides with the change in the pinning from strong to weak. This temperature/field induced transition is caused either by the magnetic impurities in LCCO:Co or by the coupling between the pancake vortices and the in-plane Josephson vortices in LCCO. These results are in agreement with early theoretical and numerical predictions.Comment: 6 pages, 4 figures, the proceedings of VORTEX VII in Physica

Wafer bonding: A flexible way to manufacture SOI materials for high performance applications

An overview is given on the use of wafer bonding for formation of Silicon-On-Insulator (SOI) materials for high performance applications. Recent developments in wafer bonding and available techniques for formation of thin semiconductor films is presented. Furthermore, a review is given on results in use of wafer bonding for formation of advanced SOI-materials. Finally, a more detailed discussion is given on the use of wafer bonding for manufacture of SOI-materials intended for high-frequency applications and SOI-materials with films of electrically insulating but highly thermally conductive materials as buried insulators

Hydrophobic low temperature wafer bonding; void formation in the oxide free interface

The objective is to investigate plasma assisted bonding processes having the potential of forming oxide-free bonded interfaces. Spontaneous low temperature hydrophobic bonding was achieved using a plasma-assisted technique. High surface energy was obtained when bonding two silicon wafers after argon plasma treatment and a subsequent dip in concentrated HF. In contrast hydrogen plasma caused bonding problems while a mix of hydrogen and nitrogen improved the bondability. A particular interest is directed toward the generation of voids as a consequence of storage at room temperature or low temperature annealing. All samples suffer from void generation both after storage at room temperature and after low temperature annealing

Hydrophobic low temperature wafer bonding; void formation in the oxide free interface

The objective is to investigate plasma assisted bonding processes having the potential of forming oxide-free bonded interfaces. Spontaneous low temperature hydrophobic bonding was achieved using a plasma-assisted technique. High surface energy was obtained when bonding two silicon wafers after argon plasma treatment and a subsequent dip in concentrated HF. In contrast hydrogen plasma caused bonding problems while a mix of hydrogen and nitrogen improved the bondability. A particular interest is directed toward the generation of voids as a consequence of storage at room temperature or low temperature annealing. All samples suffer from void generation both after storage at room temperature and after low temperature annealing