INSTABILITY OF POST-FOWLER-NORDHEIM STRESS MEASUREMENTS OF MOS DEVICES

MOS test device electrical measurements (C-VI charge pumping), perform ed after accelerated ageing stress based on Fowler-Nordheim injection, strongly modify the net oxide charge. This can lead to an incorrect e valuation of the oxide long-term stability. We ascribe the observed in stabilities to partial annealing of unstable slow states and trapped h oles which lie close to the Si/SiO2 interface. Finally we propose and compare different experimental approaches to get more ''stable'' measu rements. (C) 1997 Elsevier Science Ltd.