Microelettronica

Coordinatore scientifico: Francesco Giuseppe Della Corte

Principali Attrezzature Scientifiche Disponibili

Description	Producer	Model
Arbitrary Waveform Generator	HP	33120A
Arbitrary Waveform Generator	SONY/TEK	AWG2005
Cosfimeter	ITALTEC
Curve Tracer	Hameg	HM6042
DC Power Supply	HP	E3631A
DC Power Supply	AGILENT	6228A
Digital Oscilloscope	TEKTRONIX	TDS360
Digital Oscilloscope	LECROY	WAVESURFER 434
Digital Oscilloscope	LECROY	WAVEPRO 7100
Digital Oscilloscope	TEKTRONIX	TDS 2002
DSP Lock-in-Amplifier	SIGNAL RECOVERY	7265
Ellipsometer	GAERTNER	L116C
Frequency Counter	TEKTRONIX	CMC251
Laser Module	THORLABS	WDM-C-25-10-DM
Laser Module	THORLABS	WDM-C-27A-40-NM
Logic Analyzer	TEKTRONIX	TLA5202
Logic Analyzer	HP	54620A
Logic Analyzer	HP	54620A
Milliamperometer	ITALTEC
Modular Platform for Laser Diode Test	THORLABS	PRO 8000-4
Multimeter	HP	34401A
Multimeter	HP	34401A
Precision LCR Meter	HP	4284A
Pulse Generator	AGILENT	8114A
Semiconductor Parameter Analyzer	AGILENT	4155C
Spectrum Analyzer	ADVANTEST	R3131
Stereomicroscope	LEICA	MZ6
Stereomicroscope	LEICA	MZ9.5
Arbitrary Waveform Generator	AGILENT	33250A
Digital Oscilloscope	LECROY	WAVESURFER 454

Personale che partecipa alle attività di Laboratorio

• Prof. Riccardo Carotenuto
• Prof. Francesco Della Corte
• Prof. Fortunato Pezzimenti

Attività Scientifiche Condotte nel Laboratorio

The research interests of the Laboratory fall in the area of the integration, on a single microchip, of high-performance electronic modules, sensors, transducers and optical devices. Specifically, the following topics can be considered representative of the active researches:

Microelectronics compatible photonic materials and devices
(F. G. Della Corte, A. Macheda, S. Rao, P. Tripodi)

The research deals with the design and the experimental characterization of passive and active devices for optical communications fabricated with technologies that are compatible with the standard CMOS microelectronic processes. The target is in fact the realization of an optical bus to be used for direct communication between chips or between sub-modules embedded on the same chip (system-on-chip).

The main optoelectronic material/technology under investigation is hydrogenated amorphous Silicon (a:Si:H), whose technological and optical properties might allow the rapid deployment of a photonic layer on top of every microchip at the end of its realization process. An electro-optical modulator based on an a-Si:H/a:SiCN multistack is currently being studied, exploiting field-induced free carrier absorption as the modulation mechanisms.

Modeling and characterization of wide-gap semiconductor bipolar devices
(F.G. Della Corte, F. Pezzimenti)

The development of new devices based on wide-bandgap semiconductors, to be used in high temperature environments or in high voltage/high power appliances, more and more involves the deployment of intensive modelling efforts for the tuning of the technological parameters in view of the fabrication of optimised devices and for an effective interpretation of the experimental tests. In the last years the Group has targeted its activity toward the study of homo- and hetero-junction bipolar devices, based on numerical simulations. The emphasis has been put, in particular, on the analysis of the effects of interface defect states on the injection efficiency of a pn junction. The Group also took part at the design and realisation of several power devices, among which the first GaAs BMFET.

More recently, the Group committed itself with the design and the interpretation of the experimental characteristics of bipolar devices based on 4H-SiC. The main target of the project is the experimental evaluation of the electrical characteristics of a Bipolar Mode FET (BMFET) realised in 4H-SiC, and particularly of those characteristics that might make this device interesting in power switching applications. Due to the particular characteristics of the semiconductor under consideration, the experimental realisation requires first of all an in depth study based on simulations of the device, followed by a design activity of a device showing the requested characteristics.

Ultrasound transducers and actuators
(R. Carotenuto)

The research is focused on the theoretical and experimental study of the energy transfer mechanism in piezoelectric transducers, and the characterization of transducer arrays. It also deals with the study of composite materials for ultrasound transducers and the modeling of parasitic effects such as the cross coupling between array elements. The recently introduced capacitive micromachined ultrasound transducers (cMUT) are investigated in detail, in particular with respect to their sensitivity, bandwidth and ease of integration within microelectronic chips.

We also developed a new piezoelectric motor family, well suited for special applications, spanning from ultra-thin analog displays (thickness < 0.3 mm) to paper feeding motors in printers or credit card scanning in card readers, and to motorized probes for medical echography (sector scanning with transducers over 30 MHz). In particular, the novel concept of 'acoustic fiber' for power applications has been introduced, by proposing and realizing a flexible motor well suited to scan echographic transducers for endoscopy (motor length 500 mm and maximum diameter 3 mm). The research activity includes the design and realization of different power supply and control circuits, equipped with microprocessors, in order to exploit the special characteristics of the developed ultrasound motors (very fast mechanical dynamics and high controllability). Efforts are currently devoted to place in a theoretical framework the developed motors, using the theory of multi-port systems and power transmission lines, and to study new applications.

Image reconstruction and elaboration in ultrasound echography for medical applications
(R. Carotenuto)

The research activity is devoted to the improvement of the spatial resolution of medical echographic images. In this field, the novel concept of 'aperture extrapolation' has been introduced, successively implemented with computer simulations and using experimental data from SAFT (Synthetic Aperture Focusing Technique). The basic idea is to build the echographic image which could be obtained with a transducer with an aperture larger than that physically available by modelling the luminance variation of each pixel of the image when the transducer aperture is increased. The computational cost is very low, compared with other approaches currently under investigation in the international scientific community. The extrapolation requires only small modifications of a standard echographic hardware.

Smart RF-ID's with integrated antenna
(F. Aquilino, F.G. Della Corte, L. Fragomeni, M. Merenda, F. Zito)

The target of this research is a set of wireless devices (e.g. sensors) useful for application where a high degree of pervasivity and a low invasivity are the demand. The chips have an on-chip radiating element (loop antenna). The small antenna efficiency and the ultra low power electronic design are the main aspects currently under investigation. Several prototypes of temperature sensors, 1 mm2 in size, endowed with their loop antennas have been already designed and fabricated with standard 0.8 um and 0.35 um CMOS technology.
A parallel activity has leaded to the fabrication of fully integrated RF-ID elements, through which the expensive fabrication step of the external antenna bonding has been cut.
We also aim at the integration of power collecting elements to make the devices autonomous from an energetic point of view. For this reason small solar cells have been designed and fabricated on the same microchip.