Nitridation by No or N2o of Si-Sio2 Interfaces

X-ray photoelectron spectroscopy (XPS) and photocurrent measurements for the determination of surface recombination velocity provide complementary information on the structure of the Si-SiO 2 interface, being sensitive to the chemical nature of foreign species at the interface the former, and to intrinsic defects the latter. The comparison of the XPS N(1s) peaks determined for the Si-Si0 2 interfaces nitrided in NO or N 2 O ambients is useful to identify the species responsible for the broadening of the peak. In fact, nitridation by NO is mainly responsible for the formation of Si 3 N moieties at the silicon surface in which silicon atoms are partially oxidized; while nitridation by N 2 O proceeds with the oxidation of Si - Si backbonds to Si - N bonds, thus resulting in the formation of N(Si(O-) 3 ) 3 groups embedded in the oxide. Surface recombination velocity by photocurrent measurements gives evidence that nitridation in N 2 O is associated with an appreciable co-oxidation, while nitridation in NO is mainly associated with the passivation of interface states. Furthermore N 2 O and NO nitridation are responsible for different morphologies of the nitrided layers.