Nanotechnology-Enabled Sensors

160 Chapter 4: Nano Fabrication and Patterning Techniques
highly insulating oxide or nitride films. However, it requires an impedance
matching network which consists of inductors and capacitors. 44
Fig. 4.18 Formation of the dark and plasma regions above the target’s surface.
Magnetic fields (magnetron) can also be applied to the plasma region in
order to improve the sputtering performance. For instance, a static magnetic
field at surface of the sputtering target can be produced by a permanent
magnet. The magnetic field generated is parallel to the cathode (the
target) surface (Fig. 4.19). This magnetic field forces the secondary electrons
to move perpendicular to both the electric field (normal to the surface)
and the magnetic field (parallel to the surface). Causing these
electrons to move parallel to the cathode surface, where they form a current
loop of drifting secondary electrons (Fig. 4.19). As a result, these secondary
electrons are trapped in a region close to the target. These electrons