Radiation‐Induced Neutral Electron Trap Generation in Electrically Biased Insulated Gate Field Effect Transistor Gate Insulators

Abstract

Optically assisted electron injection was employed to quantify neutral electron trap and fixed positive charge concentrations in the gate oxides of electrically biased n-channel insulated gate field effect transistors exposed to 10 keV x-rays. This is the first known work to study the effects of an applied gate oxide field during x-ray irradiation on neutral electron trap generation. Surprisingly, the results show that neutral electron trap generation is dependent upon the gate bias, and the oxide thickness in a similar manner as positive charge buildup during irradiation. This possibly suggests an association between the two defect types. A neutral electron trap generation model is proposed in which the E~ trapped hole center transforms into a dipolar neutral electron trapping site via electron compensation by an electron.

Positive and Negative Oxygen Vacancies in Amorphous Silica

“…Our works extends the model based on electron and hole trapping at the O 3 Si=Si O 3 defect in silica (see Fig. 1) proposed earlier (1,2,8) and predict the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO 2 . We argue that the oxygen vacancies can be responsible for both the electron and hole trapping in silica.…”

Models of oxygen vacancy defects involved in degradation of gate dielectrics

“…Our work extends the model based on electron and hole trapping by the O 3 ≡Si=Si≡O 3 defect in silica (see Fig. 1) proposed earlier [1][2][3][4] and predicts the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO 2 .…”

“…Electron spin resonance (ESR) studies have demonstrated that the positive charge generated in the samples under different applied external conditions (e.g. irradiation) correlates with the E'-center generation (see, for example, [1][2][3]). This is widely considered as an indicator for the occurrence of radiation induced or pre-existing diamagnetic neutral oxygen vacancies, V 0 centers, (O 3 ≡Si=Si≡O 3 ) which can capture holes and convert into positively charged vacancies, V + centers, (O 3 ≡Si+ …·Si≡O 3 ), otherwise called E' γ -centers.…”

Radiation effects on floating-gate memory cells

“…Tunneling across the tunnel oxide (10 nm thick) will occur until the FG charge decreases and conduction is stopped by the corresponding decrease of the tunnel oxide field. 2) After capturing an electron, the trapped hole can be converted into a neutral trap [22]. If two or more neutral traps are spatially aligned, they give rise to a conductive path reproducing and multiplying that found in the case of radiation-induced leakage current (RILC) [23].…”