Lossless Electron Beam Monochromator for Enhanced Resolution in Electron Microscopy

Projektbeschreibung

Kompression anstelle von Filterung eliminiert Elektronenstrahlverluste

Die räumliche und spektrale Auflösung moderner hochauflösender Elektronenmikroskope wird durch die Energieverteilung des Elektronenstrahls eingeschränkt, die chromatische Aberrationen verursacht. „Monochromatoren“, die mechanische Spalten als Bandpassfilter verwenden, werden oft zur Korrektur eingesetzt, aber sie führen zu Verlusten beim Elektronenstrahl. Im Rahmen des ERC-finanzierten Projekts Loss-less Monochroma soll ein vereinfachter Monochromator konzipiert werden, der auf einem Einkristall im Inneren der Mikroskopsäule basiert. Infrarot-Laserpulse erzeugen im Kristall THz-Strahlung, die mit dem Elektronenstrahl in Wechselwirkung tritt und die Elektronenenergie komprimiert, anstatt sie zu filtern, wodurch Strahlverluste vermieden werden. Diese bahnbrechende Kristalltechnologie wird in konventionellen, kostengünstigen Elektronenmikroskopen nachrüstbar sein, um deren Leistung zu verbessern.

Ziel

Lossless Electron Beam Monochromator for Enhanced Resolution in Electron Microscopy

The performance of advanced high-resolution electron-microscopes (EM) is severely limited by the energy spread of the electron beam, which limits both spatial and spectral resolutions by causing chromatic aberrations. To mitigate this limitation, monochromators are used. Common monochromators have mechanical slits as a narrow band-pass filter, inherently introducing high loss to the electron beam. They are very complex and thus highly expensive. Here we propose to develop a novel electron monochromator technology that is lossless, relatively simple (and thus, cost-effective), and modular, so it can potentially be installed as an upgrade in a wide range of existing EM systems. The proposed monochromator compresses the electron energy rather than filtering it, and thus the resulting electron beam suffers no losses. We use a single crystal, located inside the microscope column, close to the incoming electron beam. Infrared laser pulses are used to generate THz radiation in the crystal which interacts with the electron beam such that the energy of the electron beam is compressed without introducing electron losses.

We aim to achieve this through three main goals: (1) Demonstrate the ability to get strong energy compression in pulsed electron mode with the advantage of low losses. (2) Demonstrate that our idea can also upgrade the performance of traditional low-cost CW operating EM such as low-voltage scanning EM (LV-SEM). (3) Commercialize our IP and penetrate the market. We developed new IP, aiming to commercialize the technology at the end of the project. We are in contact with microscope manufacturers expressing interest in our innovation. Our lossless electron beam monochromator is expected to be a game-changer in all EM applications, in particular the semiconductor inspection and medicine development markets, where high-resolution SEMs are becoming increasingly popular.