High-aspect ratio zone plate fabrication for hard x-ray nanoimaging

Karolis Parfeniukas; Stylianos Giakoumidis; Rabia Akan; Ulrich Vogt

doi:10.1117/12.2272695

23 August 2017 High-aspect ratio zone plate fabrication for hard x-ray nanoimaging

Karolis Parfeniukas, Stylianos Giakoumidis, Rabia Akan, Ulrich Vogt

Proceedings Volume 10386, Advances in X-Ray/EUV Optics and Components XII; 103860S (2017) https://doi.org/10.1117/12.2272695
Event: SPIE Optical Engineering + Applications, 2017, San Diego, California, United States

Abstract

We present our results in fabricating Fresnel zone plate optics for the NanoMAX beamline at the fourth-generation synchrotron radiation facility MAX IV, to be used in the energy range of 6–10 keV. The results and challenges of tungsten nanofabrication are discussed, and an alternative approach using metal-assisted chemical etching (MACE) of silicon is showcased. We successfully manufactured diffraction-limited zone plates in tungsten with 30 nm outermost zone width and an aspect ratio of 21:1. These optics were used for nanoimaging experiments at NanoMAX. However, we found it challenging to further improve resolution and diffraction efficiency using tungsten. High efficiency is desirable to fully utilize the advantage of increased coherence on the optics at MAX IV. Therefore, we started to investigate MACE of silicon for the nanofabrication of high-resolution and high-efficiency zone plates. The first type of structures we propose use the silicon directly as the phase-shifting material. We have achieved 6 μm deep dense vertical structures with 100 nm linewidth. The second type of optics use iridium as the phase material. The structures in the silicon substrate act as a mold for iridium coating via atomic layer deposition (ALD). A semi-dense pattern is used with line-to-space ratio of 1:3 for a so-called frequency-doubled zone plate. This way, it is possible to produce smaller structures with the tradeoff of the additional ALD step. We have fabricated 45 nm-wide and 3.6 μm-tall silicon/iridium structures.

Citation Download Citation

Karolis Parfeniukas, Stylianos Giakoumidis, Rabia Akan, and Ulrich Vogt "High-aspect ratio zone plate fabrication for hard x-ray nanoimaging", Proc. SPIE 10386, Advances in X-Ray/EUV Optics and Components XII, 103860S (23 August 2017); https://doi.org/10.1117/12.2272695

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available