UNIVERSITA’ DEGLI STUDI DI UDINE
Dipartimento di Ingegneria Elettrica Gestionale e Meccanica
1. MODELING, SIMULATION AND CHARACTERIZATION OF nano-MOSFETs
F.Driussi, P.Palestri, L.Selmi
Collaborations: CEA-LETI Grenoble, INPG Grenoble, IMEC Lovanio, ST Microelectronics Crolles, Università di Bologna, Pisa
2. 3D SILICON RADIATION SENSORS
Collaborations: Univ. di Trento, FBK-Trento, Jozef Stefan Institute, Lubiana
3. MODELING AND DESIGN OF RF CIRCUIT BLOCKS IN ADVANCED CMOS TECHNOLOGY
Collaborations: Infineon Technologies Villach, Intel Mobile Communications, Univ. Siena
4. INNOVATIVE NON VOLATILE MEMORIES
Collaborations: CEA-Leti Grenoble, Laboratorio MDM-IMM del CNR Agrate Brianza (MI)
5. POWER ELECTRONICS
Collaborations: Università di Padova, CPES Virginia Tech
MODELING, SIMULATION AND CHARACTERIZATION OF nano-MOSFETs
F.Driussi, P.Palestri, L.Selmi
The activity is focused on the experimental characterization and modelling of lateral transport in nano-MOSFETs. An approach based on the solution of the Boltzmann Transport Equation for the 2D electron gas via Monte Carlo techniques is being pursued for both nMOS and pMOS devices in Silicon as well as alternative channel material (III-V and graphene) transistors.
Tunnel-FETs are studied both with semiclassical and quantum-mechanical (NEGF) approaches.
Current studies are focused on the simulations of the main technology boosters introduced in the CMOS process, on use of graphene for RF application, on the advantages of using SiGe and III-V as channel material and on the optimization of tunnel-FETs based on Si, Ge as well as III-V materials for ultra-low voltage and minimum energy per operation.
3D SILICON RADIATION SENSORS
This activity aims at the investigation, development and optimization of a novel radiation sensor design that significantly reduces the chip volume and substantially lowers the applied voltages. The 3D radiation sensor concept has been investigated by 2D and 3D simulation. Moreover, ways to optimize the design by changing the p-spray implant on both sides of the wafer have been proposed. A detailed analysis of impact ionization coefficients in irradiated samples allowed us to identify a small but well defined reduction of the
ionization coefficients which can be input in the device simulators to improve the accuracy and predictivity of TCAD for radiated sensors. The activity is carried out in close collaboration with FBK-Trento (silicon sensor fabrication) and Univ. di Trento (characterization and modeling).
MODELING AND DESIGN OF RF CIRCUIT BLOCKS IN ADVANCED CMOS TECHNOLOGY
Our research activity in this field aims at the understanding of the advantages and limitations that innovative CMOS technologies such as technologically boosted bulk CMOS (strain and high-k), FinFETs or tunnel-FETs can have compared to conventional bulk CMOS.
In this framework, we have designed RF building blocks (VCOs and LNAs) using innovative technologies and using new techniques for the reduction of phase noise and for increasing the tuning range. The most recent developments include investigation of CMOS circuits for high frequency data transmission in automotive environments.
Other activities in this area are related to the mixed device/circuit simulations of simple digital building blocks to explore the potential of non-conventional device concepts such as finFETs and tunnel-FETs for ultra-low power operation.
INNOVATIVE NON VOLATILE MEMORIES
The research activity aims at the investigation, understanding and optimization of innovative devices and materials for non volatile memory applications for the sub 20nm technology node. Charge trapping memories have been thoroughly investigated by means of experiments and the understanding of the device and material behavior has been pursued through the development of reliable electrical and atomistic models. In particular, the model validation and calibration has been obtained by means of an extensive comparison with a wide spectrum of material analysis and electrical characterizations. The activity led us to assess the nature of the trapping behavior of the storage layers exploited by the charge trap memory devices, highlighting the physical processes involved in the memory operation.
The activity is carried out in close collaboration with CEA-LETI Grenoble (for silicon nitride based devices) and MDM-IMM laboratory of CNR in Agrate Brianza (for oxide hafnium based memories).
-Researches on high performance digital control:
In  is presented an autotuning technique for digitally controlled voltage-mode dc-dc converters based on the model reference approach. The proposed solution uses the difference between the measured system impulse response and the reference one, determined by the desired dynamic performances, and minimizes the error function acting on the regulator parameters. Two different approaches have been investigated for the evaluation of the impulse response: a deterministic one, based on duty cycle impulse, and a statistical one, based on white noise injection.
-Researches on DC-DC converter applications:
In  is investigated anew clamp topology in order to achieve the ZVS system for LED application.
-Researches on energy scavenging systems:
In  is investigated a power management architecture based on a hybrid accumulator system that utilizes the supercapacitor cell as storage element
for energy harvesting applications. The supercapacitor guarantees a longer lifetime in terms of charge cycles, it presents itself as a "green" technology compared to batteries and it has a wide range of operating temperature.
Publications in 2011
1) MICELLI et al., 3D-FBK pixel sensors: Recent beam tests results with irradiated devices. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT, vol. 650, p. 150-157, 2011
2) CRISTOFOLI A, PALESTRI P, GIORDANI M.P, CINDRO V, DALLA BETTA G.-F, SELMI L, Experimental Determination of the Impact Ionization Coefficients in Irradiated Silicon. IEEE TRANSACTIONS ON NUCLEAR SCIENCE, vol. 58, p. 2091-2096, 2011
3) R.CLERC, P.PALESTRI, L.SELMI, G.GHIBAUDO, Impact of carrier heating on backscattering in inversion layers. JOURNAL OF APPLIED PHYSICS, vol. 110, p. 104502, 2011
4) CONZATTI F., et al., Investigation of Strain Engineering in FinFETs Comprising Experimental Analysis and Numerical Simulations. IEEE TRANSACTIONS ON ELECTRON DEVICES, vol. 58, p. 1583-1593, 2011
5) PONTON D., KNOBLINGER G., ROITHMEIER A., CERNOIA F., TIEBOUT M., FULDE M., PALESTRI P., LC-VCO in the 3.3- to 4-GHz Band Implemented in 32-nm Low-Power CMOS Technology. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS. II, EXPRESS BRIEFS, vol. 58, p. 467-471, 2011
6) GRENIER P. et al., Test beam results of 3D silicon pixel sensors for the ATLAS upgrade. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT, vol. 638, p. 33-40, 2011
7) De Michielis, L.; Moselund, K.E.; Selmi, L.; Ionescu, A.M.; Corner Effect and Local Volume Inversion in SiNW FETs. Nanotechnology, IEEE Transactions on , vol.10, no.4, pp.810-816, 2011.
8) D.ESSENI, D.; F.DRIUSSI; A Quantitative Error Analysis of the Mobility Extraction According to the Matthiessen Rule in Advanced MOS Transistors. Electron Devices, IEEE Transactions on , vol.58, no.8, pp.2415-2422, 2011.
9) M.DE MICHIELIS, F.CONZATTI, ESSENI D, L.SELMI. On the Surface-Roughness Scattering in Biaxially Strained n- and p-MOS Transistors. IEEE TRANSACTIONS ON ELECTRON DEVICES, vol. 58, p. 3219-3223, 2011
10) S.M.Thomas, M.J.Prest, T.E.Whall, D.R.Leadley, P.Toniutti, F.Conzatti, Esseni D, L.Donetti, F.Gámiz, R.J.P.Lander, G.Vellianitis, P.-E.Hellström5, and M.Östling. On the role of Coulomb scattering in hafnium-silicate gated silicon n and p-channel metal-oxide-semiconductor-field-effect-transistors. JOURNAL OF APPLIED PHYSICS, vol. 110, p. 124503, 2011
11) E. VIANELLO, F. DRIUSSI, L. PERNIOLA, G. MOLAS, J.-P. COLONNA, B. DE SALVO AND L. SELMI. Explanation of the Charge-Trapping Properties of Silicon Nitride Storage Layers for NVM Devices - Part I: Experimental Evidences From Physical and Electrical Characterizations. IEEE TRANSACTION ON ELECTRON DEVICES, Vol.58, pp. 2483-2489, 2011
12) E. VIANELLO, F. DRIUSSI, P. BLAISE, P. PALESTRI, D. ESSENI, L. PERNIOLA, G. MOLAS, B. DE SALVO AND L. SELMI. Explanation of the Charge Trapping Properties of Silicon Nitride Storage Layers for NVMs - Part II: Atomistic and Electrical Modeling. IEEE TRANSACTION ON ELECTRON DEVICES, Vol.58, pp. 2490-2499, 2011
13) COSTABEBER, A.; MATTAVELLI, P.; SAGGINI, S.; BIANCO, A. Digital Autotuning of DC–DC Converters Based on a Model Reference Impulse Response, IEEE Transactions on Power Electronics, Volume: 26, Issue: 10, DOI: 10.1109/TPEL.2011.2122271, 2011 , p.2915 - 2924