The lateral high aspect ratio structures allowed the top membrane to be lifted off, enabling film characterization by XPS also inside the structure. The B 1s, C 1s and Si 2p XPS core level spectra from within the structure are presented in Fig. , showing very similar peak positions for the signals probed from the film deposited both outside and inside of the lateral high aspect ratio structure. The intensity of the Si 2p peak increases inside the structure which is explained by the presence of uncoated Si pillar tops that come in the XPS beam spot area. Since the top membrane was removed after the deposition, the pillar tops are free of boron carbide deposition.