Design of practical deflection field in nanometer-scale focused ion beam system

Two pre-lens deflectors were optimized to reduce the deflection chromatic aberration in a focused ion optical column. Correction principles of the dynamic focus lens and stigmator were researched in detail. The deflection field curvature, astigmatism and distortion can be eliminated by superposing suitable signals on the objective lens and deflectors, which effectively reduces the complexity of the ion optical column. The optical properties of the two deflectors with dynamic correction were simulated and their power supply circuit was built based on superposition theory of electric signals. When the beam current is 1 nA, the pre-lens deflectors can obtain nanometer-scale focused ion beam at the corner of 0.2×0.2 mm2.