FIB Induced DepositionFIB is a charged particle beam with a much greater mass than the charged particles (electron) used in FEB (Focused Electron Beam). As shown in several other applications/tutorials here, this greater mass allows the FIB to sputter away matter has the beam hits the surface of the targeted material. It is possible to reverse this process if a gas is introduced in the vicinity of the impact point: this is called FIB induced deposition (FID).
If the FIB remains too long onto the same point, the freshly deposited material will be sputtered away. Every time the gas is being consumed, it needs to be replenished in order to maintain a net positive yield. For this reason, once the beam as used the majority of the adsorbed gas, it moves to another location before coming back to the same point. The time between two subsequent visits is called the refresh time. Once some new molecules have been adsorbed on the surface, the beam can revisit the same point and then increase the depo thickness. A tight beam control (refresh time, beam spacing, focus, dwell time) is critical to have a successful FID since the precursor gas can be easily depleted and then cause a net deposition rate to be negative which results in material sputtering instead of deposition Different precursor gases create different depo. The most commonly depo materials are Tungsten, Platinum, Carbon and Insulator. |
