Augusto Pieracci

Experimental study of hot-carrier effects in LDMOS transistors

Hot-carrier currents and the induced degradation mechanisms in lateral double-diffused MOS (LDMOS) transistors for smart power applications are investigated in detail. Three different regions within the device where significant hot-carrier generation can occur depending on bias as well as device technological parameters have been identified. Guidelines to suppress the degradation mechanisms involving the two lightly doped regions of the device not overlapped by the gate electrode, responsible for the stronger device degradation, are provided. Devices optimized according to the given guidelines have been fabricated and demonstrate a strong hot carrier resistance.

A Wireless Body Area Sensor Network for Posture Detection

Body Area Sensor Networks (BASN) are an emerging technology enabling the design of natural Human Computer Interfaces (HCI) in the context of Ambient Intelligence. This class of interactive applications poses new challenges on sensor network design that are hard to be faced using traditional solutions optimized for environmental monitoringlike applications. In this paper we present a novel solution for wireless and wearable posture recognition based on a custom-designed wireless body area sensor network, called WiMoCA. Nodes of the network, mounted on different parts of the human body, exploit tri-axial accelerometers to detect body postures. Afterwards we discuss results of interactive performance and power consumption optimizations required to match application constraints.

Interfacing human and computer with wireless body area sensor networks: the WiMoCA solution

Wireless Body Area Sensor Networks (WBASN) are an emerging technology enabling the design of natural human–computer interfaces (HCI). Automatic recognition of human motion, gestures, and activities is studied in several contexts. For example, mobile computing technology is being considered as a replacement of traditional input systems. Moreover, body posture and activity monitoring can be used for entertainment and health-care applications. However, until now, little work has been done to develop flexible and efficient WBASN solutions suitable for a wide range of applications. Their requirements pose new challenges for sensor network designs, such as optimizing traditional solutions for use as environmental monitoring-like applications and developing on-the-field stress tests. In this paper, we demonstrate the flexibility of a custom-designed WBASN called WiMoCA with respect to a wide range of posture and activity recognition applications by means of practical implementation and on-the-field testing. Nodes of the network mounted on different parts of the human body exploit tri-axial accelerometers to detect its movements. The advanced digital Micro-electro-mechanical system (MEMS) based inertial sensor has been chosen for WiMoCA because it demonstrated high flexibility of use in many different situations, providing the chance to exploit both static and dynamic acceleration components for different purposes. Furthermore, the sensibility and accuracy of the sensing element is perfectly adequate for monitoring human movement, while keeping cost low and size compact, thus meeting our requirements. We implemented three types of applications, stressing the WBASN in many aspects. In fact, they are characterized by different requirements in terms of accuracy, timeliness, and computation distributed on sensing nodes. For each application, we describe its implementation, and we discuss results about performance and power consumption.

Design and implementation of WiMoCA node for a body area wireless sensor network

This paper presents the design and implementation of a wireless sensor node for a Motion Capture system with Accelerometers (WiMoCA). It is composed by a tri-axial integrated accelerometer a microcontroller and a wireless transceiver WiMoCA nodes have been exploited to build a Wireless Body Area Sensor Network (WBASN) that allows to implement a wireless/wearable distributed gesture recognition system where nodes are mounted on many parts of the human body. We describe the hardware architecture and all the software layers supporting the recognition system. We also show characterization experiments on WiMoCA nodes that highlight how their performance and power consumption levels make them suitable to HCI applications.

Tunneling bursts for negligible SILC degradation

This paper suggests the use of high-voltage tunneling bursts for (virtually) SILC-free current injection in ultra-thin MOS structures and indicates the possibility of fast programming of tunnel-based nonvolatile memories.

Introducing tangerine: a tangible interactive natural environment

In this paper we describe TANGerINE, a tangible tabletop environment in which users can interact with digital contents manipulating tangible smart objects. Such objects provide continuous data about their status through the embedded wireless sensors, while an overhead computer vision module tracks their position and orientation. Merging sensing data, the system is able to detect a richer language of gestures and manipulations both on the tabletop and in its surroundings, enabling for a more expressive interaction language across different contexts.

Fast tunneling programming of nonvolatile memories

This work investigates the possibility of programming nonvolatile memories in the ns time scale, for possible replacement of DRAMs, at least in special applications where low-power requirements do not allow frequent data refreshing. The study demonstrates the possibility of using high voltage tunneling pulses to achieve program times significantly shorter than 100 ns with acceptable oxide damage.

A new characterization method for hot-carrier degradation in DMOS transistors

This paper presents an original method based on capacitance measurements, that is able to localize and estimate hot-electron-induced oxide charge in double-diffused MOS (DMOS) transistors. The method is validated by means of two-dimensional (2-D) numerical simulation. Preliminary results obtained with state-of-the-art devices are presented as example of application.

Extraction of channel doping profile in DMOS transistors

This paper presents the first method to characterize the doping profile and the length of the channel of double-diffused MOS transistors, typically used in smart power ICs. The method, based on capacitance measurements, is validated by means of 2D numerical simulation and applied to transistors fabricated with advanced 0.6 /spl mu/m technology.

Fast programming/erasing of thin-oxide EEPROMs

This work demonstrates that conventional thin-oxide EEPROM cells can be programmed (erased) in the nanosecond time scale with voltages lower than 18 V and still feature data retention times of the order of a few hours after 100 K program/erase (P/E) cycles. Our results suggest that thin-oxide nonvolatile (NV) memory devices can be suitable for fast read/write dynamic applications, at least when high cycling endurance is not a primary specification.