  In contrast to static holographic phase shifters, which are restricted to
specific electron beam energies and microscope settings, Boersch phase shifters
are promising for creating programmable arrays for generating two- and
three-dimensional electron beam patterns. We recently demonstrated a
three-element Boersch phase shifter device [Thakkar et al., J. Appl. Phys. 128
(2020), 134502], which was fabricated by electron beam lithography and is
compatible with up-scaling. However, it suffers from parasitic beam deflection
and resulting cross-talk. Here, we report a five-layer phase shifter device,
which is based on a metal-insulator-metal-insulator-metal structure (as
originally envisioned by Boersch) that reduces cross-talk. We demonstrate a
three-element Boersch phase shifter that shows minimal beam deflection of
voltage-controlled three-electron-beam interference patterns in a transmission
electron microscope operated at 200 keV. The feasibility of using such
multi-element phase shifter arrays is discussed.
