TURN-AROUND EFFECTS OF STRESS-INDUCED LEAKAGE CURRENT OF ULTRATHIN N2O-ANNEALED OXIDES

Studies of the thickness dependence on stress-induced leakage current (SILC) have been performed in the thickness range of 41 to 87 Angstrom for N2O-annealed and O-2-grown oxides. N2O-annealed oxide shows signi ficantly reduced SILC leakage currents. Furthermore, SILC currents wer e found to increase with decreasing oxide thickness, as reported earli er. However, a ''turn-around'' effect at similar to 50 Angstrom has be en observed in these films. SILC currents begin to decrease when oxide thickness is scaled below 50 Angstrom. This turn-around effect can be explained using the trap-assisted tunneling model. For thicknesses eq ual or less than 41 Angstrom, defect-related current and direct tunnel ing current become dominant over SILC current. Our results indicated t hat for N2O-based oxides in the ultrathin thickness regime, stress-ind uced leakage currents become less significant.