Electrical stress and plasma-induced traps in SiO2

High field stress and N-2 reactive ion etching (RIE)-mode plasma-generated positive oxide charge in thin (13 nm) SiO2-Si structures have been studied. A threshold field of about 8.5-9 MV/cm for positive charge formation is fo und. It is established that both high field stress and PIE-like plasma trea tment create nonuniformly distributed positive charge in the depth of the o xide, in the form of bulk traps and slow states. It is found that the gener ation of neutral bulk traps is an attribute, only of the high field stressi ng. The structural nature of the process-induced traps is discussed. It is suggested that the impact ionization of oxygen vacancies accounts For the p ositive charge and neutral trap creation. (C) 2000 Elsevier Science Ltd. Al l rights reserved.