TEM characterisation of Accumulation Low Schottky Barrier MOSFET with PtSi contacts.

The Schottky barrier MOSFET has been proposed recently as an alternative to traditional MOSFET for sub-100 nm devices because of its many advantages. The optimisation of the fabrication process of Accumulation Low Schottky Barrier (ALSB) MOSFET’s on SOI substrates requires a solution of critical material issues. One of the most attractive features is the low source and drain contacts resistance of Schottky barriers formed at the silicide/silicon interface, which is essential to provide performance gain when device dimensions are reduced. The current in ALSB-MOSFET is controlled by the contacts resistance, thus in order to obtain a higher current low Schottky barriers are required. The choice of PtSi as a silicide material is based on the fact that it has one of the lowest Schottky barrier on p-type silicon [1-2]. The TEM specimens were prepared by the method described in [3] and studied in the JEM-200CX transmission electron microscope operating at 200kV. The cross-sectional transmission electron microscopy (XTEM) was used to study the formation of the PtSi contacts. The PtSi layer was formed by the solid-state reaction between the 15 nm thick Pt layer and the silicon substrate after annealing at 400 ºC (Fig. 1). Th