Depth resolved Doppler broadening spectroscopy in thin metallic films

Within this contribution the examination of thin metallic films by (C)DB ((coincident) Doppler broadening) measurements at different temperatures is presented. Systems with a gold or copper layer with a thickness between 20 and 500 nm were produced by evaporation deposition on silicon substrates. Doppler broadening and positronium fraction were examined in order to investigate annealing processes. In addition, theses samples as well as gold-copper-silicon systems were studied by depth resolved CDB measurements with the goal to obtain information about temperature dependent diffusion processes at the interface. These measurements were performed by use of the highly intensive positron beam NEPOMUC. Depth resolved DB measurements are used for the determination of the positron diffusion length which is highly sensitive to defect concentration. At high temperatures the thermic desorption of positronium can be detected and additionally considered to determine the diffusion length. Depth resolved CDB measurements allow the detection of the chemical surrounding of defects in layered structures. Recently a new heatable sample holder has been set up in order to achieve a sample temperature up to 1000 K.