Direct X-ray and electron-beam lithography of halogenated zeolitic imidazolate frameworks

Abstract

Integrating metal-organic frameworks (MOFs) in microelectronics has disruptive potential because of the unique properties of these microporous crystalline materials. Nanoscale patterning is a fundamental step in the implementation of MOFs in miniaturised solid-state devices. Conventional MOF patterning methods suffer from a low resolution and poorly defined pattern edges. Here, we demonstrate for the first time resist-free, direct X-ray and e-beam lithography of MOFs. This process avoids etching damage and contamination, and leaves the porosity and crystallinity of the patterned MOFs intact. The resulting highquality patterns have a record sub-50 nm resolution, far beyond the state of the art in MOF patterning and approaching the mesopore regime. The excellent compatibility of X-ray and e-beam lithography with existing microfabrication processes, both in research and production facilities, provides an avenue to explore the integration of MOFs in microelectronics further. This approach is the first example of direct lithography of any type of microporous crystalline network solid, and marks an important milestone in the processing of such materials.

Negative X-ray expansion in cadmium cyanide

“…As our understanding of material–X-ray interactions improves, we can start to use X-ray radiation as a design tool in its own right (as opposed to simply a diagnostic one); recent experiments in the X-ray lithography of Metal–Organic framework (MOF) thin films are an exciting new application in that space. 53 The systematic studies employed here to identify the negative X-ray expansion in cadmium cyanide are an important starting point.…”

Oriented growth of semiconducting TCNQ@Cu3(BTC)2 MOF on Cu(OH)2: crystallographic orientation and pattern formation toward semiconducting thin-film devices

“…the use of pre-patterned SAM), the fabrication of MOF patterns by photolithography used in current microfabrication technology is a promising method because of the formation of high-resolution MOF patterns and compatibility with existing semiconductor fabrication processes. 18,[34][35][36][37] Although photolithography techniques can efficiently prepare precise MOF patterns, the fabrication of MOF patterns with crystallographic orientation (oriented MOF patterns) by integration with conventional lithography technology remains a challenge. In particular, the oriented MOF patterns of semiconducting TCNQ@Cu 3 (BTC) 2 contribute to the development of MOF-based thin-lm devices.…”

Avoiding the Center‐Symmetry Trap: Programmed Assembly of Dipolar Precursors into Porous, Crystalline Molecular Thin Films

“…[ 33 ] Concerning photonic applications of such surface‐mounted MOFs (SURMOFs), a huge variety of appropriate chromophoric linkers has been synthesized, and numerous chromophore‐based MOFs and SURMOFs with interesting optical properties have been realized. [ 34,35 ] In addition, with regard to lateral patterning of SURMOFs, first results using photo‐ [ 36 ] or electron beam lithography [ 37,38 ] have been reported.…”