Generation of oxide charge and interface states by ionizing radiation and by tunnel injection experiments

Journal Article · Wed Dec 01 04:00:00 UTC 1982 · IEEE Trans. Nucl. Sci.; (United States)

DOI:https://doi.org/10.1109/TNS.1982.4336389· OSTI ID:6093299

Knoll, M; Braunig, D; Fahrner, W R

Results of irradiation and high field tunnel injection experiments on MOS capacitors are discussed. The midgap voltage shift as a function of dose is caused by hole trapping only. In the case of tunnel injection, the generation of electron-hole pairs by impact ionization requires a much larger electron density and high fields. Thus a model of charge build-up is established which takes into account the hole trapping in neutral oxide states, the subsequent electron trapping in now positively charged states and detrapping of captured electrons. By means of this model, the prediction of the radiation hardness of MOS devices is feasible, provided that the impact ionization coefficient ..cap alpha.. is known accurately. The proposed model is verified by a sequence of irradiation and injection steps. The generation of oxide charge is accompanied by an increase in interface state density D /SUB it/ with a distribution, which peaks at about 0.15 eV above midgap, in both experiments. The results indicate that the generation of interface states is proportional to the amount of trapped holes. The injection experiments yield the following characterization of the type of the interface states: acceptor type states above midgap and donor type states below midgap. This confirms the fact that the variation of the midgap voltage is the distinguished point to evaluate the change of the oxide charge, since the interface charge becomes neutral for this case.

• Research Organization: Hahn-Meitner Inst. for Nuclear Research, Glienicker Strasse 100, 1000 Berlin 39
• OSTI ID: 6093299
• Journal Information: IEEE Trans. Nucl. Sci.; (United States), Journal Name: IEEE Trans. Nucl. Sci.; (United States) Vol. 29:6; ISSN IETNA
• Country of Publication: United States
• Language: English

Related Subjects

440200* -- Radiation Effects on Instrument Components
Instruments
or Electronic Systems
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CAPACITORS
CHALCOGENIDES
CHARGED PARTICLES
ELECTRIC POTENTIAL
ELECTRICAL EQUIPMENT
ELECTRON DENSITY
EQUIPMENT
HOLES
INTERFACES
IONIZING RADIATIONS
IONS
IRRADIATION
MOS TRANSISTORS
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
RADIATIONS
SEMICONDUCTOR DEVICES
TRANSISTORS
TRAPS
TUNNEL EFFECT