GaAs on Si: Device Applications.- Substrate Considerations.- Majority-Carrier Devices.- Minority-Carrier Devices.- Conclusions.- Ion Beam Synthesis in Silicon.- The Ion Implantation Process.- Buried SiO2 Layers in Si.- Buried Monocrystalline CoSi2 Layers in Si.- Conclusions.- Ion Beam Processing of Chemical Vapor Deposited Silicon Layers.- Ion Beam Effects.- Epitaxy of Deposited Layers.- Polycrystal Formation.- Technology and Devices for Silicon Based Three-Dimensional Circuits.- 3D-Technology.- Device Characteristics.- Features of 3D-Circuits.- Demonstrators.- Conclusions.- Integrated Fabrication of Micromechanical Structures on Silicon.- Mechanical Properties of Silicon.- Thermal Properties.- Fabrication Techniques.- Etching.- Anisotropic Etching.- Boron Doped Etch Stop.- Electrochemical Etch Stop.- Embedded Layers.- Surface Microstructures.- Bonding of Layers.- Electrostatic Bonding.- Oxide Bonding.- Bonding to Metals.- Conclusion.- Micromachining of Silicon for Sensors.- Physical Properties of Silicon.- Transduction Techniques.- Fabrication Techniques.- Pressure Sensors.- Accelerometers.- Microresonator Sensors.- Optical Microresonator Sensors.- Conclusions.- Micromachining of Silicon for Sensors.- Hybrid or Monolithic Approach for optoelectronics: That is the question.- About the Hybrid Approach Material Competitors.- Silicon Based Technologies developed at LETI.- Planar and Channel waveguide Properties of IOS Technologies.- Field of Activities.- Integrated Optical Spectrum Analyser (IOSA).- Integrated Optical Sensors.- Optical Communication Applications.- Optical Memories.- Conclusion.- Principles and Implementation of Artificial Neural Networks.- Binary Networks.- Analog Networks.- Miscellaneous Networks.- Future VLSI Networks.- Conclusions.- List of Participants.