Two signals from silicon nitride (Si3N4) film have been measured by the electron spin resonance (ESR) method at very low temperature of about 10 K. The two signals correspond to silicon dangling bonds of an Si3Si0 state and an N3Si0 state. The total spin density is about 2×1017 cm-3. The evaluation of metal-nitride-oxide-silicon (MNOS) non-volatile memory devices has revealed that Si3N4 film has electron traps of about 7×1018 cm-3 and hole traps of about 1.2×1020 cm-3. These results have led us to believe in the coexistence of Si3Si+ and N3Si-, which are not measured by the ESR method in the equilibrium state. Thus, an electron-trapped state represents a negatively charged state of the coexisistence of Si3Si0 and N3Si-, and a holetrapped state represents a positively charged state of the coexisistence of Si3Si+ and N3Si0. We, therefore, propose a 2-trap model in which electrons and holes are separately trapped.
Emission cross sections were measured for the Lyman series of hydrogen atom split from SiH4 molecule by electron impact in the energy range below 1000 eV. It was found that the emission cross sections for the Lyman series depend on the principal quantum number n according to the relaion Qem ∝ n-3.3.