The impact of focused ion beam induced damage on scanning spreading resistance microscopy measurements

Abstract

Scanning Spreading Resistance Microscopy is a well-established technique for obtaining quantitative two- and three-dimensional carrier profiles in semiconductor devices with sub-nm spatial resolution. However, for sub-100 nm devices, the use of focused ion beam becomes inevitable for exposing the region of interest on a sample cross section. In this work, we investigate the impact of the focused ion beam milling on spreading resistance analysis and we show that the electrical effect of the focused ion beam extends far beyond the amorphous region and depends on the dopant concentration, ion beam energy, impact angle, and current density. For example, for dopant concentrations between 1.0 × 1020 and 1.5 × 1016 cm−3 we observe dopant deactivation at least between 23 and 175 nm for a glancing 30 keV ion beam. Further, we show that dopant deactivation is caused by defect diffusion during milling and is not directly impacted by the presence of Gallium in the sample. Later, we also discuss potential ways to mitigate these effects.

Template-assisted growth of Ga-based nanoparticle clusters on Si: effect of post-annealing process on the Ga ion beam exposed 2D arrays fabricated by focused ion beam nanolithography

“…Diffusion of implanted Ga into the target material, in lateral and primary beam directions, and the effect of annealing on Ga diffusion were reported. Depending on Ga ion dose, energy, microstructure of target material, incident angle and target temperature, maximum lengths of Ga diffusion up to several hundred nanometres, along the lateral direction, were noticed [21,46,47]. In crystalline Si, the cause of damage is attributed to ion channelling effects in addition to point defect creation and migration (rather than the long beam tail effect).…”

“…Accumulated pure Ga on the surface of Si was often found to be unstable at room temperature due to its low melting point. Segregation of Ga droplets on Si (100) and the effects of implantation scheme, annealing temperature (as high as 600 • C) and Arsenic flux to form stable GaAs compound are earlier reported for large area scans [47]. Therefore, post-annealing temperature, duration and the annealing atmosphere are the critical parameters and they need to be carefully optimized in order to obtain precipitation of stable Ga-based compounds on the surface.…”

Local Structural Modifications in Metallic Micropillars Induced by Plasma Focused Ion Beam Processing

“…Its significance becomes particularly pronounced regarding sample preparation accuracy for in situ and operando tests at the micro-and nanoscale. However, caution must be exercised, because FIB milling involves bombarding the material of interest with high-energy ions, which can induce surface alterations and structural defects, including recrystallization, amorphization, formation of new phases, and material redeposition [4,5]. Therefore, the alterations introduced by FIB milling can significantly impact the validity of experimental results.…”

Improving the Performance of the ToGoFET Probe: Advances in Design, Fabrication, and Signal Processing

“…SPM maps the distributions of physical properties by simultaneously measuring tip-sample interactions and the topography [2][3][4][5][6]. Various SPM techniques are used for electrical measurements, including electrostatic force microscopy (EFM) [2,7,8], Kelvin probe force microscopy (KPFM) [3,9,10], scanning capacitance microscopy (SCM) [4,11,12], and scanning spreading resistance microscopy (SSRM) [13][14][15]. These techniques measure contact potential differences [3,10], dopant concentration profiles [7,9], and local capacitance [8,12].…”