Spatial distributions of trapping centers in HfO2∕SiO2 gate stacks

Abstract

A methodology to analyze charge pumping (CP) data, which allows positions of probing traps in the dielectric to be identified, was applied to extract the spatial profile of traps in SiO2∕HfO2 gate stacks. The results suggest that traps accessible by CP measurements in a wide frequency range, down to few kilohertz, are located within or near the interfacial SiO2 layer rather than in the bulk of the high-k film.

Breakdown characteristics of nFETs in inversion with metal/HfO2 gate stacks

“…Low frequency CP measurements were shown to probe the defects spatially distributed deep into IL [17]. Young et al showed that the probing depth of CP frequency in kHz order is around 1.2 nm from the IL/Si interface [11].…”

Characterization of HfO2 films deposited on 4H-SiC by atomic layer deposition

“…These changes are believed to be caused by the HfO 2 / SiO 2 interface charge. 18,19 The stack measured in the experiment may be simplified to a system with two insulators with different dielectric constants and two charge densities localized at the HfO 2 / SiO 2 and SiO 2 / SiC interfaces, respectively. Considering a flatband condition, it can be shown from Gauss law that E ox = ox / ox and E HfO 2 = ͑ ox + HfO 2 ͒ / HfO 2 .…”

Beyond SiO2 technology: Simulation of the impact of high-κ dielectrics on mobility

“…In our investigation of an interfacial layer we have concentrated on an SiO 2 interfacial layer. This is justified by a number of different studies [20][21][22] which have shown that the interfacial layer between Si and Hf oxide consists of a SiO 2 layer or in general a SiO x type layer, and any diffusion of Hf into the interfacial layer is only minor and occurs only at the very edge of the interfacial layer with Hf. However, as yet there are very little data on the stoichiometric content (x value) of the SiO x layer, we have assume an SiO 2 interfacial layer.…”