1560xb cross beam

HeLa cells were plated on square, home-made gridded glass pieces (1 cm × 1 cm) and incubated with the internalization solution as described previously. Later, the samples were fixed with 2.5% glutaraldehyde (EM grade; Sigma-Aldrich, St. Louis, MO, USA), dehydrated through a graded series of ethanol/water mixtures up to 100% ethanol, and dried by the critical point method. The initial localization of the silicon chips was made by bright-field optical microscopy (BFOM), using an Eclipse ME600 upright optical microscope (Nikon Minato City, Tokyo, Japan) at ×100 magnification (0.8 NA LU Plan ELWD 3.5). Images were recorded on an 8-bit color CCD camera (DXM1200F, Nikon, Minato City, Tokyo, Japan). The cells of interest were mapped on the gridded glass pieces and further localized and observed by Scanning Electron Microscopy (SEM) at 5 keV (Auriga, Carl Zeiss GmbH, Oberkochen, Germany). Once observed by SEM, the same cells were studied by Focused Ion Beam–Scanning Electron Microscopy (FIB–SEM) using Ga⁺ ions in a dual beam instrument (1560XB Cross Beam, Carl Zeiss GmbH, Oberkochen, Germany).

The optical microscope Leica DM 4000 M was used to analyze the printed layers. Electrical measurements were carried out in a semi-automatic Cascade Microtech Summit Series 12000 probe station using a semiconductor parameter analyzer Keithley 4200 and taking into account the IEEE 1620 standard for test methods for the characterization of organic transistors and materials41 (link). The probe station was adapted to work with the soft and flexible plastic substrate. Different smart characterization protocols were developed based on LabVIEW programs which perform a variety of electrical measurements in order to analyze the failure origins. Additionally, in-situ optical investigation was performed by capturing microscopic images of each of the TFTs during the process of electrical characterization. Profilometry measurements were carried out with a Veeco Dektak 150. Scanning electron microscopy (SEM) was performed with a Zeiss Auriga microscope. The system is equipped with a focused ion beam (FIB) tool Zeiss 1560XB Cross Beam. FIB cuts were performed to obtain cross-sectional images of the layer stack in order to determine the thickness and the structure of the individual layers. The cuts were 150 μm long to avoid single point measurements in non-regular areas and were done in the center of the TFTs far away from the edge regions.