Ballisticity Saturation by Unscalable Reflections

The intrinsic limit on ballisticity of ultra-scaled transistors is investigated. A novel probing technique is presented, which locally resolves the loss of incident fluxes. This projection reveals the scalable and unscalable components of reflection. The poor ballisticity is explained by non-equilibrium distribution around the potential barrier, which triggers a substantial unscalable reflections.