Positive charging of thermal SiO2 layers:: hole trapping versus proton trapping

Positive charging of thermal SiO2 layers on (100)Si related to injection of protons is compared to the hole trapping. Proton trapping has initial probability close to 100% and shows little sensitivity to the annealing-induced oxygen deficiency of SiO2. In contrast, the hole trapping in as-grown SiO2 shows much lower efficiency which increases strongly upon annealing in qualitative correlation with higher density of O(3)drop Si . defects (E' centers) detected by electron spin resonance. Despite these differences, the neutralization of positive charges induced by holes and protons has the same cross section, and in both cases is accompanied by atomic H release. Therefore, hole trapping is associated with release of a proton from a O(3)drop Si-H defect and its subsequent trapping in the oxide. (C) 2001 Elsevier Science B.V. All rights reserved.