On stress induced leakage current in 5 and 3 nm thick oxides

The stress induced leakage current (SILC) in Si/SiO2 structures with thin g ate oxides has a steady-state component which increases drastically when th e oxide thickness decreases. It is generally agreed that the SILC is due to electron tunnelling trough stress-induced traps. However, it was observed that the SILC, created by Fowler-Nordheim injection, decays continuously wh en, after stress, the samples are positively or negatively biased at a low voltage. The decay is irreversible as long as the gate oxide is not biased at a high voltage. The present article adds complementary observations. It shows, first that the above phenomenon is observed in 3.5 nm thick oxides, secondly, that this phenomenon is stable as long as the temperature stays b elow 200 degrees C, and thirdly, that during the SILC decay, the interface state density does not diminish. (C) 2000 Elsevier Science Ltd. All rights reserved.