Schottky contacts are investigated on n-type 4H-SiC by electrical measurements and microstructural analyses to understand the behaviour of such a barrier. Titanium and tungsten were deposited after RCA cleaning as surface preparation of SiC. Electrical characterisation shows that the Fermi level is partially pinned by interfacial surface states attributed to an interfacial layer between the metal and the SiC. This interfacial layer is characterised by X-ray reflectivity, transmission electron microscopy and Auger electron spectroscopy. An attempt is made to correlate microstructural observations with electrical measurements.