Conduction and trapping mechanisms in SiO2 films grown near room temperature by multipolar electron cyclotron resonance plasma enhanced chemical vapor deposition

Abstract

Silicon dioxide layers with stoichiometric composition and excellent electrical properties were deposited at a substrate temperature of 60 °C with an electron cyclotron resonance plasma source. This work is focused on determining the electrical conduction and trapping mechanisms of the deposited films. From the temperature dependence of current density–electric field characteristics, Fowler–Nordheim tunneling was found to be the dominant conduction mechanism in SiO2 films obtained with low silane flow and at low pressure. For layers deposited with higher silane flows and higher pressures, the current at low biases is highly dependent on temperature. Positive charge was measured at the Si/SiO2 interface during low electric stress, while electrons were trapped at the interface for electric fields higher than 7 MV/cm. Constant current stress measurements confirmed that low silane flow and low total pressure are suitable deposition conditions for obtaining a film comparable to thermally grown oxide from the reliability point of view.

Low-Temperature SiO[sub 2] Layers Deposited by Combination of ECR Plasma and Supersonic Silane/Helium Jet

“…Thus, although the current flowing through the low-pressure oxide ͓highest resistivity of 6 ϫ 10 15 ⍀ cm measured at the onset of Fowler-Nordheim ͑F-N͒ tunneling at 6 MV/cm͔ is mainly due to F-N tunneling, the currents through the high-pressure oxides are ruled by trap-related mechanisms. 10,21 The XPS measurements indicate that the O/Si 4+ ratio is 2 and hardly changes within the experimental error. Nevertheless, the refractive index ͑extracted at 1.96 eV͒ decreases considerably with increasing the pressure ͑Fig.…”

Fabrication and properties of GeSi and SiON layers for above-IC integrated optics

“…High density PECVD is known to provide better quality films compared to conventional PECVD. Earlier work in our group had shown that ECR plasma depositions of SiO 2 and Si 3 N 4 around room temperature led to films with very low hydrogen content [29,30]. This was followed by deposition of high quality silicon dioxide at 150°C using ICPECVD [31] with the same deposition system as in the present work.…”

An investigation of capacitance aging model for extreme low-k and high-k dielectrics

“…Since the transient leakage current due to the charge trapping is wellmatched by a Power Law on time and so is the trap generation due to stress [5][6], the capacitance drift characteristics for both ELK and HK can be explained reasonably well by the charge trapping/ detrapping processes. …”

“…Where J is the transient current [5]; N is number of trap charges [6] C is the measured capacitance, and is the VAF of the capacitance drift. The validity of capacitance drift based lifetime model in Eq.…”