Why would ion implantations impact on nanotechnology be limi

Why would ion implantation’s impact on nanotechnology be limited? How about spin-on glass dopants for nanodevice manufacturing?

Solution

Ion implantation is one of a number of surface modification processes that is emerging as an economical and viable process for improving the near-surface tribological properties of engineering components. In many engineering situations, material selection is often based on a compromise of bulk mechanical properties and near-surface tribological properties, with neither at their optimum values. As a result, there is considerable interest in fabrication processes, such as ion implantation, that make it possible to retain the bulk properties of a given compound yet still achieve desirable tribological properties in near-surface regions. Ion implantation is a process by which virtually any element in the periodic chart can be injected into near-surface regions of any solid using a beam of high-velocity ions with energies typically ranging from 10 keV up to several MeV. As the ions slow down in the material, they are distributed at depths ranging from a few nanometers to several micrometers, depending on the particle energy, angle of incidence, and substrate composition. Depending on the ion type, mass, energy, dose, deposition temperature, and substrate composition, the chemical, electrical, thermal, microstructural, and crystallographic properties of near-surface regions can be significantly altered to improve the friction and wear performance of the component. Some of the advantages and limitations of ion implantation relative to other surface modification processes.     The main disadvantage of ion implantation is that it is a line-of-sight process, making manipulation of components with complex shapes necessary to ensure uniform implantation of critical surfaces. However, it should be noted that recent advances in plasma-source technology have led to a novel ion-implantation process called plasma-source ion implantation that is not limited to line-of-sight implantations from one direction. Ion implantation is a nonequilibrium process that generates a large number of mobile defects in near-surface regions in addition to deposition of the implanted species. Spin-on glass (SOG) is a mixture of SiO2 forming chemicals and dopants (often boron or phosphorous) that is suspended in a solvent solution. The SOG is applied to a clean silicon wafer by spin-coating. The SOG is our dopant source.     Spin-on doping is much more uniform than gas diffusion doping in a furnace tube. Typically, variance across a wafer is between 0.5% and 1% and variance wafer to wafer ranges between 1% to 2%.