Fluorides for 2D Next-Generation Nanoelectronics

The IRDS roadmap considers two-dimensional (2D) materials a promising option for scaling electronicdevices down to atomic dimensions. While there has been a lot of progress regarding 2D semiconductors,all electronic devices require suitable insulators as well. Although a major show-stopper, insulators havereceived far less attention and their is no clear roadmap as to which insulators can be used for ultimatelyscaled nanoelectronics.My group was recently first to demonstrate back-gated 2D FETs using ultrathin calcium fluoride (CaF2)as an insulator. Based on these promising results, I firmly believe that fluorides, which are ionic crystalswith often very wide bandgaps, can efficiently address the major challenges: (i) Although relativelyexotic materials, their growth is considerably better established than that of any 2D material. (ii) CaF2 canbe epitaxially grown layer-by-layer on silicon substrates and likely also on 2D semiconductors. As theirF-terminated inert surface supports van der Waals epitaxy of 2D materials, they could be the missing linkbetween 3D substrates and 2D semiconductors. (iii) The low-defectivity of the inert CaF2 surface willsignificantly improve device performance and stability. Thereby, fluorides will allow novel 2D devices tomake the leap from promising concepts to highly performant and stable real devices.F2GO will establish fluorides as a key enabler for 2D nanoelectronics by successfully demonstratingdevice architectures which were previously impossible to fabricate with sufficient performance due toinadequate insulators. I will do so by investigating selected fluoride-based devices for key technologies: (i)steep slope devices for CMOS logic (Cold Source FETs) at the ultimate scaling limit to allow sub-100 mVoperation and (ii) ultra-scaled non-volatile memory devices (Flash and TRAM). Thereby, F2GO will pavethe way for fluoride-based nanoelectronics at the ultimate scaling limit as required for the generations2030+.