ProximityEffekt

ProximityEffekt is a term used in physics and engineering to describe phenomena in which physical effects extend beyond their nominal source area due to proximity to other materials or structures. In microfabrication and electronics, it most often refers to the proximity effect observed in electron-beam lithography, where electron scattering causes unintended exposure of nearby resist regions. In superconductivity, the term describes the leakage of superconducting correlations into an adjacent non-superconducting metal.

In electron-beam lithography, primary electrons scatter elastically and inelastically in resist and substrate, producing secondary and backscattered electrons that deposit dose outside the intended footprint. The resulting proximity blur reduces resolution and alters feature sizes, especially for dense patterns or high-aspect-ratio features. The effect depends on dose, beam energy, substrate material, resist type, and geometry. Mitigation uses proximity correction (PEC): adjusting the local dose or exposure pattern using models of electron scattering, often guided by Monte Carlo simulations and calibration with test patterns; can also involve multi-pass writing, or optimized resist and substrate choices.

In superconductivity, the proximity effect occurs when a superconductor is in contact with a normal metal or ferromagnet. Cooper pairs leak into the adjacent material over a characteristic coherence length, inducing superconducting correlations and modifying properties such as the critical temperature and resistance. This effect enables devices like SNS junctions, superconducting quantum interference devices (SQUIDs), and certain nanoscale sensors.