The influence of Coulomb centers located in HfO2/SiO2 gate stacks on the effective electron mobility

Abstract

Articles you may be interested inOn the role of Coulomb scattering in hafnium-silicate gated silicon n and p-channel metal-oxide-semiconductorfield-effect-transistors Analysis of electron mobility in HfO 2 / TiN gate metal-oxide-semiconductor field effect transistors: The influence of HfO 2 thickness, temperature, and oxide charge

Origin and passivation of fixed charge in atomic layer deposited aluminum oxide gate insulators on chemically treated InGaAs substrates

“…We identified oxygen and aluminum dangling bonds ͑DBs͒ as the origin of the fixed charge. First-principles calculations predicted possible passivation of both O and Al DBs, which would neutralize fixed charge, and this prediction was confirmed experimentally; postmetallization forming gas anneal removed most of the fixed charge in ALD-Al 2 In recent years, dimensional scaling of complementary metal-oxide-semiconductor ͑CMOS͒ devices has brought about serious interest in introducing high-mobility channel layers composed of III-V materials. 1 A longstanding problem for structures that include an oxide/III-V semiconductor interface has been the presence of interfacial defects that can trap charge during device operation.…”

“…However, defects present in the bulk of a high permittivity ͑high-k͒ oxide layer that forms a relatively passive interface with III-V channel materials may be of equal importance because of their potential to increase gate leakage current, and to form fixed charge that will scatter carriers in the channel and alter the threshold voltage of the device. 2 Many of the high-k dielectric materials investigated to replace SiO 2 in Si-channel MOS devices are grown as thin films with significant areal densities of fixed charge. 3 However, the density of fixed charge either near the interface between ALD-Al 2 O 3 and the channel or in the bulk of Al 2 O 3 layers deposited on III-V materials such as InGaAs has not been studied carefully.…”

Electron Mobility Degradation Due to Remote Coulomb Scattering in Ge MOSFET

“…Especially the remote Coulomb scatterings (RCS) from Ge gate stacks are not reported to data, even though the RCS is found to play an important role in Si based MOSFETs with high-k materials. [10], [15][16][17][18] In this paper, the RCS is experimentally investigated for Ge MOSFETs. The RCS from electric dipole at Al 2 O 3 /GeO x interface is found to play a significant role on electron mobility degradation.…”

High resolution photoemission study of SiOx/Si(111) interface disruption following in situ HfO2 deposition

“…2 Different explanations have been proposed to account for this observed degradation including the coupling of carriers to surface softoptical phonons 3,4 and remote-Coulomb scattering. 5,6 Both of these mechanisms are reported to have a reduced impact on mobility degradation as the thickness of the SiO x interlayer is increased however, this negatively impacts on the minimum equivalent oxide thickness ͑EOT͒ which can be realized. Controlling the thickness of the interfacial silicon oxide is therefore a prerequisite to achieving EOT values below 1.0 nm which are required for the continued scaling of device geometries.…”

“…Therefore, this observed effect of interface disorder would have a similar dependence on the thickness of a SiO 2 buffer layer as the other proposed explanations for mobility degradation. [3][4][5][6] While the dielectric constant of the interfacial hafnium silicate layer would be expected to be greater than that of an equivalently thick SiO 2 layer, it would be difficult to compensate for the disrupted nature of the Si/ SiO 2 interface. In fact, it could be speculated that the conventional hydrogen based passivation techniques used to improve the electrical characteristics of the thermally formed Si/ SiO 2 interface for device application would be less effective in the case of the hafnium silicate-silicon interface because of the induced disorder.…”