A method of forming a lamella (27, 204, 304, 404, 504, 604, 704, 804, 904, 1004, 1104) having an observation face for transmission electron microscope observation of a feature of interest in the observation face, comprising: directing a charged particle beam toward a work piece in the vacuum chamber of a charged particle beam system to induce deposition from a precursor gas of a protective layer above the feature of interest,; directing a focused ion beam toward the sample to mill one or more fiducials (201, 202) near the feature of interest; directing (102, 103) a focused ion beam to mill cavities on both sides of the region of interest to form a lamella; characterized by: from each side of the lamella, directing (104, 105) a focused ion beam to mill progressively closer to the observation face from the cavity, successively milling to a decreased depth as the beam approaches the region of interest to provide a bottom surface (510, 611) that decreases in depth as the bottom surface approaches the observation face, the ions in the focused ion beam having a first landing energy; after milling progressively closer to the observation face from the cavity, milling to remove material separating the cavities to leave tabs supporting the cavity; after milling to remove material separating the cavities, directing (108, 109) an ion beam toward the observation face, the ion beam having a second landing energy, lower than the first landing energy; and wherein the protective layer is a carbon protective layer, the carbon protective layer having a sputtering rate matched to the sputtering rate of the work piece. directing a charged particle beam toward a work piece in the vacuum chamber of a charged particle beam system to induce deposition from a precursor gas of a protective layer above the feature of interest,; directing a focused ion beam toward the sample to mill one or more fiducials (201, 202) near the feature of interest; directing (102, 103) a focused ion beam to mill cavities on both sides of the region of interest to form a lamella; characterized by: from each side of the lamella, directing (104, 105) a focused ion beam to mill progressively closer to the observation face from the cavity, successively milling to a decreased depth as the beam approaches the region of interest to provide a bottom surface (510, 611) that decreases in depth as the bottom surface approaches the observation face, the ions in the focused ion beam having a first landing energy; after milling progressively closer to the observation face from the cavity, milling to remove material separating the cavities to leave tabs supporting the cavity; after milling to remove material separating the cavities, directing (108, 109) an ion beam toward the observation face, the ion beam having a second landing energy, lower than the first landing energy; and wherein the protective layer is a carbon protective layer, the carbon protective layer having a sputtering rate matched to the sputtering rate of the work piece. from each side of the lamella, directing (104, 105) a focused ion beam to mill progressively closer to the observation face from the cavity, successively milling to a decreased depth as the beam approaches the region of interest to provide a bottom surface (510, 611) that decreases in depth as the bottom surface approaches the observation face, the ions in the focused ion beam having a first landing energy; after milling progressively closer to the observation face from the cavity, milling to remove material separating the cavities to leave tabs supporting the cavity; after milling to remove material separating the cavities, directing (108, 109) an ion beam toward the observation face, the ion beam having a second landing energy, lower than the first landing energy; and wherein the protective layer is a carbon protective layer, the carbon protective layer having a sputtering rate matched to the sputtering rate of the work piece.