O-vacancies in (i) nano-crystalline HfO2 and (i) non-crystalline SiO2 and Si3N4 studied by X-ray absorption spectroscopy.
Performance and reliability in semiconductor devices are limited by electronically active defects, primarily O-atom and N-atom vacancies. Synchrotron X-ray spectroscopy results, interpreted in the context of two-electron multiplet theories, have been used to analyze conduction band edge, and O-vacancy defect states in nano-crystalline transition metal oxides, e.g., HfO2, and the noncrystalline dielectrics, SiO2, Si3N4 and Si-oxynitride alloys. Two-electron multiplet theory been used to develop a high-spin state equivalent d2 model for O-vacancy allowed transitions and negative ion states as detected by X-ray absorption spectroscopy in the O K pre-edge regime. Comparisons between theory and experiment have used Tanabe-Sugano energy level diagrams for determining the symmetries and relative energies of intra-d-state transitions for an equivalent d2 ground state occupancy. Trap-assisted-tunneling, Poole-Frenkel hopping transport, and the negative bias temperature instability have been explained in terms of injection and/or trapping into O-atom and N-atom vacancy sites, and applied to gate dielectric, and metal-insulator-metal structures.
North Carolina State University, Raleigh, NC 27695-8202, USA.
Gerald
G
Lucovsky
Leonardo
L
Miotti
Karen Paz
KP
Bastos
D003198:Computer Simulation; D003460:Crystallization; D004579:Electron Transport; D006195:Hafnium / Q000737:chemistry*; D008422:Materials Testing; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D012666:Semiconductors; D017655:Silicon Compounds / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*
D010087:Oxides; D017655:Silicon Compounds; C545179:hafnium oxide; D012822:Silicon Dioxide; C032734:silicon nitride; D010100:Oxygen; D006195:Hafnium