Positron study of plasma-enhanced chemical vapor deposited silicon nitride films

Abstract

Positron annihilation spectroscopy has been combined with Auger electron depth profiling, elastic recoil detection, Fourier-transform infrared spectroscopy, and capacitance-voltage measurements to study silicon nitride films grown by plasma-enhanced chemical vapor deposition. For silicon-rich films the positron lineshape parameter is very close to that of undefected silicon, consistent with a strong hydrogen passivation effect. With increasing nitrogen content in the films, there is an increase in the number of unpassivated vacancy complexes available to trap positrons prior to annihilation. Detailed analysis gives a measure of the electric field induced in the silicon substrate by the presence of charge trapped in the silicon nitride near the interface. These results agree qualitatively with electrical measurements. Both the charge and the electric field are found to decrease with increasing nitrogen content. Incorporation of a small amount of oxygen in the films leads to a suppression of the feature in the positron spectrum associated with vacancy complexes in favor of a spectrum typical of oxygen related defects.

High-Quality Nitrogen-Doped Fluorinated Silicon Oxide Films Prepared by Temperature-Difference-Based Liquid-Phase Deposition

“…The improvement of leakage current with the NH 4 OH concentration is due to the increase in the number of Si-F 2 and Si-N bonds, which passivate and neutralize Si dangling bonds of LPD SiOF films. 22,23 The leakage current density of the film is on the order of 10 -8 A/cm 2 under 1.5 MV/cm and on the order of 10 -10 A/cm 2 under 0.2 MV/cm with the NH 4 OH molar concentration fixed at 0.8 M. The leakage current density increases approximately linearly with voltage at very low electric fields. The ohmic behavior is due to the hopping conduction mechanism of trapped electrons by dangling bonds.…”

Electrical Properties of Fluorine-Doped Oxynitride Films Prepared by Photoillumination Liquid-Phase Deposition

“…The better electrical characteristics of photo-LPD-SiON:F are from higher F and N concentrations, which passivate and neutralize Si dangling bonds of LPD-SiON:F films. [18][19][20] From I-V and C-V measurements, the electrical characteristics of LPD-SiON:F and photo-LPD-SiON:F films were dominated by the bulk defects and interface traps. The electrical characteristics of photo-LPD-SiON:F films were improved with higher fluorine and nitrogen concentrations.…”

High Quality Fluorinated Silicon Dioxide Films Prepared by Temperature-Difference-Based Liquid-Phase Deposition with Ammonium Hydroxide Incorporation

“…The improvement of leakage current is due to the increases of SiuF and SiuN bonds, which passivate and neutralize Si dangling bonds of the LPD-SiOF films. 22,34,35 Basically, the conduction mechanism at low electric fields is due to the hopping conduction mechanism of trapped electrons by dangling bonds. Schottky mechanism dominates at high electric fields.…”