Influence of the beam scan direction during focused electron beam induced deposition of 3D nanostructures

We present evidence that during focused electron beam induced deposition of 3D micro- and nanostructures, different growth rates are obtained when scanning the beam towards different directions, as well as on different sides of a growing structure. The effects of electron scattering are taken into account and shown to account only partially for this observation. We propose an interpretation in terms of gas dynamics around the deposits. Our observation and description of this effect could serve the future design of complex shapes.