Université Mohamed Premier, Faculté des Sciences, Dépt de Physique, (L.E.A.A), route Sidi Maafa, BP 524, Oujda, Morocco
Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS-CNRS), 7 avenue du colonel Roche, 31077 Toulouse, France
In this paper, we present the theoretical and experimental results of the influence of a charge trapped in ultra-thin oxide of metal/ultra-thin oxide/semiconductor structures (MOS) on the I(Vg) current-voltage characteristics when the conduction is of the Fowler-Nordheim (FN) tunneling type. The charge, which is negative, is trapped near the cathode (metal/oxide interface) after constant current injection by the metal (Vg<0). Of particular interest is the influence on the (Vg) shift over the whole I(Vg) characteristic at high field (greater than the injection field (>12.5 MV/cm)). It is shown that the charge centroid varies linearly with respect to the voltage Vg. The behavior at low field (<12.5 MV/cm) is analyzed in référence A. Aziz, K. Kassmi, Ka. Kassmi, F. Olivié, Semicond. Sci. Technol. 19, 877 (2004) and considers that the trapped charge centroid is fixed. The results obtained make it possible to analyze the influence of the injected charge and the applied field on the centroid position of the trapped charge, and to highlight the charge instability in the ultra-thin oxide of MOS structures.
(Received November 11 2004)
(Revised April 26 2005)
(Accepted May 17 2005)
(Online publication September 14 2005)