A method is provided, along with a corresponding apparatus, for filling a high aspect ratio hole without voids or for producing high aspect ratio structures without voids. A beam having a diameter smaller than the diameter of the hole is directed into the hole to induced deposition beginning in the center region of the hole bottom. After an elongated structure is formed in the hole by the beam-induced deposition, a beam can then be scanned in a pattern at least as large as the hole diameter to fill the remainder of the hole. The high aspect ratio hole can then be cross-sectioned using an ion beam for observation without creating artefacts. When electron-beam-induced deposition is used, the electrons preferably have a high energy to reach the bottom of the hole, and the beam has a low current, to reduce spurious deposition by beam tails.