Here, we present on the progress of developing a multilayered accelerator structure designed to boost the 50 keV output of a DC electron gun to energies of~ 400 keV powered by a single high-energy terahertz (“THz”) pulse. An integrated piezo-actuated mirror inside the matchbox sized structure enables fine-tuning of the electric field in the interaction region for efficient acceleration and helps reduce the complexity of the optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.