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Focused Ion Beam (FIB) systems can be used to generate controlled micro- and nano-features on a solid surface. Prediction of surfaces fabricated in this way requires knowledge of the rate of removal of the target material in order to simulate the evolution of the surface. In this paper we present a continuous-time model of this process that allows us to predict the shape of trenches and freeform surfaces under the action of FIB. This type of model is appropriate when the points that describe the discrete trajectory of the beam (the line connecting consecutive dwell points) are close enough that the craters generated on the surface overlap. In the case of a straight beam path with constant dwell time, a trench of uniform depth is generated under these conditions. This simplified approach considerably reduces the computing time needed to simulate the process, without significantly reducing the accuracy of the predicted surface. Calibration of the model for a particular FIB setup and workpiece involves only a small number of experimental trials. The predictions of the model have been tested on a single crystalline Boron p-doped Si target material for several different beam paths. The depth and shape of the cross section of single and overlapping trenches with constant dwell time are predicted with high accuracy. The model was also used to predict three freeform surfaces, where the dwell time varies along each line of the beam path. Atomic force microscopy topography measurements show that the average relative error between the measured and simulated profiles is 2–10% depending on the complexity of the machined surface.

In this work, focused ion beam (FIB) milling of different structures is studied and compared for two different electronic materials, i.e., silicon (Si) and silicon carbide (SiC). Results show that the same processing parameters yield different trench cross sections for Si and SiC, even when the different material removal rates (MRR) are taken into account. In order to investigate more complex structures, nanocone arrays were fabricated in Si and SiC. The difference in the shape of the trench cross section and complex structures can be mainly explained by the significant difference in the angle dependent MRR for both materials. Other effects which occur during FIB irradiation by the non-ideal beam shape such as swelling and damage outside of the purposely processed region are emulated and sensitively studied by scanning probe microscopy techniques such as atomic force microscopy (in-line and off-line) and scanning spreading resistance microscopy, respectively, for SiC and the results are compared with those for Si.

Scanning probe microscopy techniques and, in particular, scanning spreading resistance microscopy (SSRM) were used for a detailed characterization of focused ion beam (FIB) induced damage in the surrounding of purposely irradiated areas on silicon. It is shown that the damaged area detected using these techniques extends up to several micrometers around the irradiated structures. The influence of the key FIB processing parameters on the FIB induced damage was examined. Parameters which were taken into account are the ion dose (from 1012 to 1018 cm−2), the milled structure size (circle diameters from 0.25 to 10 µm), the beam energy (from 10 to 30 keV), and the beam current (from 1.5 to 280 pA). Moreover, the influence of the SSRM settings on the measurement results was investigate d. Settings which were considered are the bias voltage and the force applied to the tip during the SSRM analysis. High resolution transmission electron microscopy and secondary ion mass spectroscopy analyses were performed to validate the SSRM results. Scattering between Ga ions and residual gas particles in the vacuum chamber of the FIB tool is identified as the main reason for the observed damaged area.

Scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM) were used to analyze focused ion beam (FIB) induced lateral damage around milled structures on silicon. For this purpose, circular shaped structures were realized, and the influence of the implanted Ga dose (ranging from 10^1^5 to 10^1^7cm^-^2) and of the patterned area dimension (diameters ranging from 1 to [email protected]) on the damage were examined. It is shown that the extension of the lateral damage around FIB milled structures is much larger than the area of the purposely irradiated regions (up to a factor of 5) and increases with both, Ga dose and pattern diameter. Besides, the unique capability of SCM and SSRM techniques for the detection of FIB induced damage is demonstrated. In particular, it is shown that their high sensitivity to low densities of defects allows detecting larger damaged areas compared to Atomic Force Microscopy (AFM) topography maps.

Scanning spreading resistance microscopy (SSRM) has been applied to study focused ion beam (FIB) induced damage in silicon in dependence on ion irradiation doses from 1012 cm-2 to 2·1016 cm-2. Starting from the lowest dose, SSRM detects increasing spreading resistance (SR) with increasing dose. For doses from 2·1013 cm-2 to 4·1014 cm-2, a slight decrease of SR is measured whereas for higher doses SR again slightly increases. The results are explained by physical effects like decreased carrier mobility due to increased scattering, amorphisation of silicon and precipitation of implanted Ga ions. The results clearly prove that SSRM is well suited for the fast detection of ion beam induced damage with high lateral resolution.