Novel methods for measuring diameter of focused ion beam

Two methods are proposed for directly measuring the diameter of a focused ion beam from the secondary electron intensity profile obtained by scanning the beam across either a cleaved edge of or an alignment mark on a GaAs substrate. The calculation of the secondary electron intensity profile is based on the Monte Carlo simulation of the implanted ion trajectories. The experimental results agreed well with the calculated ones. Using these methods, beam diameters can easily be measured without special tools.