References of "Baert, Bruno"
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See detailElectrical modelling of interface traps in GeSn MOS structures
Baert, Bruno ULg; Cerica, Delphine; Schmeits, Marcel ULg et al

Conference (2014, November 13)

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See detailImpact of traps on the electrical characteristics of GeSn/Ge diodes
Baert, Bruno ULg; Gupta, Somya; Gencarelli, Federica et al

Poster (2014, September 15)

Germanium-tin alloys are currently receiving a lot of attention as materials for high performance MOSFET devices. Much interest is focused on the direct band gap for Sn concentrations above 8-10% and the ... [more ▼]

Germanium-tin alloys are currently receiving a lot of attention as materials for high performance MOSFET devices. Much interest is focused on the direct band gap for Sn concentrations above 8-10% and the achievement of high mobility values, which can be further increased by the strain due to the lattice mismatch with Ge or Si. GeSn is therefore expected to play a key role in the development of either source and drain stressors for Ge p-MOSFETs or for GeSn channel MOSFETs. However, despite recent tremendous progress in the growth of such materials, the impact of defects at the interface between Ge and GeSn has not been completely characterized. As the processing of diodes contains many of the steps necessary to the fabrication of MOSFET devices, we have investigated the effect of traps on the electrical characteristics of p-GeSn/n-Ge diodes, made from GeSn layers grown by CVD on Ge and in-situ doped with Boron. Using temperature-dependent current-voltage (I-V) and capacitance- voltage (C-V) measurements, we have calculated the ideality factor of the diodes, the activation energy of the reverse saturation current and the carrier concentration of the Ge substrate. In this work, based on the comparison with results obtained from numerical simulations, we discuss these characteristics in view of assessing the extent to which electronic trap states in these heterostructures affect their electrical properties. [less ▲]

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See detailElectrical characterization of pGeSn/nGe diodes
Baert, Bruno ULg; Gupta, Somya; Gencarelli, Federica et al

Conference (2014, June 03)

I-V characteristics of pGeSn/nGe diodes have been measured and show very good properties. Simulations of the same structure are able to reproduce most of the observed behavior and point to the ... [more ▼]

I-V characteristics of pGeSn/nGe diodes have been measured and show very good properties. Simulations of the same structure are able to reproduce most of the observed behavior and point to the predominating influence of parameters such as the band gap energy of the GeSn layer. C-V characteristics showing little frequency dependence have also been measured, and their analysis for the determination of the carrier concentration is confirmed by simulations. More investigations, including the effect of temperature and other defects at the interface or in the bulk of either layers are still required in order to explain some of the observed behaviors, notably the reverse saturation current. [less ▲]

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See detailStudy of the energy distribution of the interface trap density in a GeSn MOS structure by numerical simulation of the electrical characteristics
Baert, Bruno ULg; Schmeits, Marcel ULg; Nguyen, Ngoc Duy ULg

in Applied Surface Science (2014), 291

Using a custom-made numerical simulation tool, we performed a systematic study of the energy distribution of the interface trap density in a GeSn MOS structure and of their effect on the electrical ... [more ▼]

Using a custom-made numerical simulation tool, we performed a systematic study of the energy distribution of the interface trap density in a GeSn MOS structure and of their effect on the electrical characteristics such as C–V and impedance spectra. Interface traps with various densities of states and energies in the bandgap have been investigated and the application of the conductance method was assessed. Based on a theoretical analysis, we obtained, as key results, direct connections between microscopic parameters of the structures and experimentally accessible features of the simulated macroscopic quantities. A straightforward relationship between the interface state density and the peaks in the conductance response is also highlighted. The dependence of the peak characteristics on the trap states was identified, as well as the effects of traps extending over large energy ranges in the bandgap. [less ▲]

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See detailElectrical Activity of Threading Dislocations and Defect Complexes in GeSn Epitaxial Layers
Gupta, Somya; Simoen, Eddy; Asano, Takanori et al

Conference (2013, June 04)

Detailed reference viewed: 109 (15 ULg)
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See detailStudy of interface trap density in a GeSn MOS structure by numerical simulation of the electrical characteristics
Baert, Bruno ULg; Schmeits, Marcel ULg; Nguyen, Ngoc Duy ULg

Conference (2013, May)

The semiconducting alloy germanium tin (GeSn) is expected to play an important role in the development of high mobility channel materials for next generation CMOS and optoelectronic devices. The two most ... [more ▼]

The semiconducting alloy germanium tin (GeSn) is expected to play an important role in the development of high mobility channel materials for next generation CMOS and optoelectronic devices. The two most interesting features of this material, which is compatible with mainstream Si technology, are its tunable direct band-gap and the possibility to induce strain due to the lattice mismatch with Ge and Si, thereby increasing the holes and electrons mobilities. It has been shown that the interface trap density can be under- or overestimated in Ge-channel MOSFETs when applying conventional measurement techniques such as the conductance method. As this effect is common in low band-gap materials, we expect that it also occurs for GeSn. Following our previous work on metal/GeSn/Ge structures, we have therefore applied our home-built numerical simulation software to a metal/oxide/GeSn MOS structure in order to investigate the result of the presence of such interface states. We discuss possible effects of the interface trap density, interface trap energy and temperature on the electrical characteristics. Successive simulations of both the steady-state and ac small-signal regimes give access to measurable quantities such as the admittance spectrum and the C-V curves. A physical interpretation can be attributed to their variations and an overall comparison can be made with results obtained from equivalent electrical circuit analysis. [less ▲]

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See detailImpedance Spectroscopy of GeSn-based Heterostructures
Baert, Bruno ULg; Nakatsuka, Osamu; Zaima, Shigeaki et al

in ECS Transactions (2013), 50(9), 481-490

In this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the basic semiconductor equations. We developed a numerical formalism based ... [more ▼]

In this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the basic semiconductor equations. We developed a numerical formalism based on a drift-diffusion model including a trap level and applied it to typical GeSn-based heterostructures by focusing on the electrical response under small-signal alternating current regime. The results demonstrate that our method provides an access to both microscopic and macroscopic properties, and thereon, to a physical interpretation of the electrical characteristics of GeSn-based structures by linking measurable quantities to micro-scale variations in the structures. [less ▲]

Detailed reference viewed: 111 (39 ULg)
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See detailImpedance spectroscopy of GeSn/Ge heterostructures by a numerical method
Baert, Bruno ULg; Nakatsuka, Osamu; Zaima, Shigeaki et al

in 222nd ECS Meeting, 2012 (2012)

In this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the semiconductor equations. We developed a numerical formalism based on a ... [more ▼]

In this work, we investigated the electrical characteristics of p-GeSn/p-Ge and p-GeSn/n-Ge structures obtained by simulation of the semiconductor equations. We developed a numerical formalism based on a drift-diffusion model including a trap level and applied it to typical GeSn-based heterostructures by focusing on the electrical response under small-signal alternating current regime. The results demonstrate that our method provides an access to both microscopic and macroscopic properties, and thereon, to a physical interpretation of the electrical characteristics of GeSn-based structures by linking measurable quantities to micro-scale variations in the structures. [less ▲]

Detailed reference viewed: 52 (8 ULg)
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See detailNew method for photovoltaic solar cell physical parameters extraction
Aazou, Safae ULg; Ibral, A.; Assaid, M. et al

Conference (2011)

Photovoltaic energy is one of the most important renewable energies. This type of energy, unlike other energy sources, is clean, safe, and abundant. The photovoltaic solar energy is based on the ... [more ▼]

Photovoltaic energy is one of the most important renewable energies. This type of energy, unlike other energy sources, is clean, safe, and abundant. The photovoltaic solar energy is based on the conversion of sunlight into direct current by solar cells. In order to increase the efficiency of the photovoltaic conversion and for a better understanding of the solar cell behavior, an accurate knowledge of the cell physical parameters is required. In this work, the solar cell is considered as a generator and the one-diode equivalent circuit is retained. This electronic circuit modeling the solar cell contains a diode with its reverse saturation current and its ideality factor, parasitic series and shunt resistances and a photocurrent generator. In this paper, a new physical parameters extraction method is presented, for the first time to our knowledge, which is based on the current-voltage characteristics and on the analytical expression of the output voltage given in term of the Lambert W function. This method gives all the physical parameters without any approximation or introduction of initial values. To test the efficiency of the presented method, a comparative study with other extraction methods is done. The obtained results are in good agreement. [less ▲]

Detailed reference viewed: 364 (68 ULg)