0000000000276361
AUTHOR
Robin Degraeve
Distribution and generation of traps in SiO2/Al2O3 gate stacks
In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/ Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. (C) 2007 Elsevier Ltd. All rights reserved.
Origin of the substrate current after soft-breakdown in thin oxide n-MOSFETs
In this paper is presented an experimental investigation on the origin of the substrate current after soft-breakdown in n-MOSFETs with 4.5 nm-thick oxide. At lower voltages this current shows a plateau that can be explained with the generation of hole-electron pairs in the space charge region and at the Si-SiO2 interface, and to carrier diffusion between the channel and the substrate. At higher voltages the substrate current steeply increases with voltage, due to trap-assisted tunneling from the substrate valence band to the gate conduction band, which becomes possible for gate voltages higher than the threshold voltage. Measurements on several devices at dark and in the presence of light, …
Profiling of traps in SiO2/Al2O3 gate stack by the charge pumping technique
In this paper, we present our results on the distribution and generation of traps in a SiO 2 /A1 2 O 3 transistor. The investigation has been carried out by using charge pumping measurements, both variable voltage and frequency techniques, and constant voltage stress. By increasing the amplitude of the gate pulse we observe an increase of the charge recombined per cycle closely related to the contribution of shallow traps near the SiO 2 /Al 2 O 3 interface. By reducing the pulse frequency we measure an increase in the charge pumping current due to traps located deeper in the Al 2 O 3 . By combining charge pumping and constant voltage stress measurements, we found that the traps are mostly g…
Characterization of soft breakdown in thin oxide NMOSFETs based on the analysis of the substrate current
We have investigated the properties of soft breakdown (SBO) in thin oxide (4.5 nm) nMOSFETs with measurements of the gate and substrate leakage currents using the carrier separation technique. We have observed that, at lower gate voltages, the level of the substrate current exhibits a plateau. We propose that the observed plateau is due to the Shockley-Hall-Read (SHR) generation of hole-electron pairs in the space charge region and at the Si-SiO/sub 2/ interface. At higher voltages, the substrate current steeply increases with voltage, due to a tunneling mechanism, trap-assisted or due to a localized effective thinning of the oxide, from the substrate valence band to the gate conduction ban…