Homoepitaxial bulk 4H SiC-off-axis commercial wafers were investigated after in situ hydrogen etc... more Homoepitaxial bulk 4H SiC-off-axis commercial wafers were investigated after in situ hydrogen etching on a hot wall chemical vapor deposition (HWCVD).We have performed test etching on several process conditions in order to study the surface defects reduction or transformation. A detailed map of bulk defects has been obtained by optical microscopy inspection to mark interesting position of investigated area and to identify the same area after chemical etching, with the aim to compare the defect evolution after hydrogen etching in the reactor. The highlighted defects area was analysed by means of atomic force microscopy and Micro Raman spectroscopy in order to obtain morphological and structural information. On the etched surface bulk wafer a epilayer was grown by HWCVD reactor to study the development of marked defects. The etched surfaces show a significant defect density reduction and present a good surface morphology.
In article number 1902941, Alessandro Chiolerio and co-workers describe, the converse piezo-elect... more In article number 1902941, Alessandro Chiolerio and co-workers describe, the converse piezo-electro-kinetic (CPEK) effect, which is a nonequilibrium electric-field-driven surface atom drift able to introduce structural anisotropy on former spherical metallic nanoparticles, resulting in an elongation of the whole nanocomposite hundred-fold times the electrostriction effect.
The present work compares the influence of different polymer matrices on the performance of plana... more The present work compares the influence of different polymer matrices on the performance of planar asymmetric Resistive Switching Devices (RSDs) based on silver nitrate and Ionic Liquid (IL). PolyVinyliDene Fluoride-HexaFluoroPropylene (PVDF-HFP), PolyEthylene Oxide (PEO), PolyMethyl MethAcrylate (PMMA) and a blend of PVDF-HFP and PEO were used as matrices and compared. RSDs represent perhaps the most promising electron device to back the More than Moore development, and our approach through functional polymers enables low temperature processing and gives compatibility towards flexible/stretchable/wearable equipment. The switching mechanism in all the four sample families is explained by means of a filamentary conduction. A huge difference in the cyclability and the On/Off ratio is experienced when changing the active polymers and explained based on the polymer crystallinity degree and general morphology of the prepared nanocomposite. It is worth noting that all the RSDs discussed here present good switching behaviour with reasonable endurance. The current study displays one of the most cost-effective and effortless ways to produce an RSD based on solution-processable materials.
The fabrication of resistive switching devices is an important technological topic nowadays since... more The fabrication of resistive switching devices is an important technological topic nowadays since they have been pointed out as the fundamental building block for the future neuromorphic computing devices. Among the different materials developed for this purpose, polymer nanocomposites with electrical bistability are of fundamental importance due to their several advantages in terms of flexibility, low cost and sustainability. In this work we developed a method to tune the electrical response of various polymeric matrices by modulating their physical properties. Silver nanoparticles are grown in-situ in different polymeric matrices by
Real-time observation of the filament formation and annihilation (grey area corresponds to tungst... more Real-time observation of the filament formation and annihilation (grey area corresponds to tungsten nanoprobe). (a) Filament formation at set threshold (orange color path corresponds to the formed filamentary path). (b) Filament dissolution at reset threshold (magenta color corresponds to the annihilation of the filamentary path). (c) Further filament formation.
In this paper, an innovative process flow developed to improve the thermal resistance of power IC... more In this paper, an innovative process flow developed to improve the thermal resistance of power ICs was presented. In this field, one of the major device failure mechanisms is related to the high temperatures reached during the working cycles due to the extremely critical electrical current densities. Therefore, heat transfer and dissipation are crucial aspects that need continuous improvements. Usual approaches to face this issue deal with package heat sinks design, solder selection, and wafer thinning. In this paper, a novel technological approach was settled, in which heat sinks microstructures were successfully integrated at wafer level stage on standard p-in diodes. To this aim, the bulk Si on the backside was partially replaced with Cu, a material characterized by a higher thermal conductivity material. Moreover, the well microstructures filled by Cu provide the advantage of wafer self-support, without requiring dedicated and more expensive thinning and handling technologies. An extensive characterization of the final devices was also carried out to evaluate the process and the thermal and electrical improvements. Finally, a failure analysis on selected devices was performed to identify any critical issue with the standard packaging process.
Back plate electroplating for high aspect ratio processes
Microelectronics International, 2017
Purpose In this process the electrical contact is brought to the backside of a standard silicon w... more Purpose In this process the electrical contact is brought to the backside of a standard silicon wafer. The details of the entire process are disclosed, from the photolithography processes to the electrodepositing step, and a model for electrical contact was designed. Design/methodology/approach The localized Cu growth of high aspect ratio (AR) microstructures was obtained through an SU-8 photolithography by exploiting the optimal adhesion on the silicon surface and the possibility of generating thick layers with a single spun process Findings The experimental results showed an unexpected behaviour that is theoretically explained in detail considering the energy band theory. The obtained geometries showed a remarkable 6:1 AR without any adhesion problem. The non-invasive front-side manipulation represents a noteworthy improvement and simplification for the design of a multi-step production process. Originality/value An alternative technological approach, called back plate electroplat...
Biorecognition is a central event in biological processes in the living systems that is also wide... more Biorecognition is a central event in biological processes in the living systems that is also widely exploited in technological and health applications. We demonstrate that the Electrolyte Gated Organic Field Effect Transistor (EGOFET) is an ultrasensitive and specific device that allows us to quantitatively assess the thermodynamics of biomolecular recognition between a human antibody and its antigen, namely, the inflammatory cytokine TNFα at the solid/liquid interface. The EGOFET biosensor exhibits a superexponential response at TNFα concentration below 1 nM with a minimum detection level of 100 pM. The sensitivity of the device depends on the analyte concentration, reaching a maximum in the range of clinically relevant TNFα concentrations when the EGOFET is operated in the subthreshold regime. At concentrations greater than 1 nM the response scales linearly with the concentration. The sensitivity and the dynamic range are both modulated by the gate voltage. These results are expla...
Novel dual step irradiation process for the in situ generation and patterning of silver nanoparti... more Novel dual step irradiation process for the in situ generation and patterning of silver nanoparticles in a photocured matrix was developed.
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Papers by denis perrone