Effect of High-k Oxide on Double Gate Transistor Embedded in RF Colpitts Oscillator

This paper present a comprehensive analysis of LC Colpitts Oscillator built around a DGMOS (Double Gate Metal Oxide Semiconductor) transistor using high-k technology. A mixed- mode simulation is involved, applying a quantum model to the device whereas the rest of the considered circuit is governed by Kirchhoff‟s laws. The quantum device model correspond to 2D numerical calculations based on self- consistent codes coupling Poisson and Schrödinger equation along the transport direction, considering an effective mass approximation. A comparison with Drift Diffusion model (DDM) is made in order to point out importance of quantum effect in this nanometer device. The impact of high-k oxide gate is investigated and analyzed; the results confirm that the high-k is an interesting alternative to reduce tunneling gate current of the DGMOS transistor but reach the same drain one. Considering the oscillator, our goal is focused on the analysis of its phase noise. The Linear Time Variant (LTV) model of phase noise is considered. It is based on the Impulse Sensitivity Function (ISF) which describes carefully the sensitivity of an oscillator to a parasite impulse current injection in different nodes of the circuit. The obtained results pointed out that the ISF function is sinusoidal and its period is nearly the same of the oscillator output signal for different dielectric oxide. It also states that the phase noise of a Colpitts oscillator is not affected by the use of the high-k materials. Finally this method, if extended, is a good tool to investigate a perturbation response on such circuits

Collection of substantial amount of fine and ultrafine particles during the combustion of miscanthus and forest residues in small and medium scale boilers for morphological and chemical characterizations

Renewable energies are destined to play a very important role in the future world energy balance. Among these energies, biomass production and utilization is growing considerably since it offers the possibility to provide partial substitution of fossil fuels. If health impacts of fine particles (PM2.5) from diesel combustion are well documented (Gangwar et al., 2012), those from biomass combustion need substantial information and improvements. Size fractionations of PM2.5 have to be performed in order to both determine morphological and chemical characteristics, these properties being essential for biological effects. Particulate matter was sampled during combustion of miscanthus and forest residues in medium and small scale biomass boilers (400 kW from Köb Pyrot and 40 kW from REKA). Fly ashes from medium scale boiler were sampled with a cyclone device and their granulometry was studied with both optical microscope and Malvern laser granulometer. PM2.5 (sized in the range of 0.4 μm to 2.07 μm) from low scale boiler were sampled using a DEKATI DGI impactor modified for substantial PM collection. A quick overview of setup modifications for manual impactor will be developed. Particles were observed using fluorescence microscopy. A semi-quantitative method to compare fly ashes fluorescence was developped using ImageJ (Schneider et al., 2012). Speciation of organic compounds Polycyclic Aromatic Hydrocarbon (PAH) and Humic Like Substances (HULIS) was determined on PM2.5 and fly ashes. A correlation between observed fluorescence and concentration was attempted

Effect of High-k Oxide on Double Gate Transistor Embedded in RF Colpitts Oscillator

This paper present a comprehensive analysis of LC Colpitts Oscillator built around a DGMOS (Double Gate Metal Oxide Semiconductor) transistor using high-k technology. A mixed- mode simulation is involved, applying a quantum model to the device whereas the rest of the considered circuit is governed by Kirchhoff‟s laws. The quantum device model correspond to 2D numerical calculations based on self- consistent codes coupling Poisson and Schrödinger equation along the transport direction, considering an effective mass approximation. A comparison with Drift Diffusion model (DDM) is made in order to point out importance of quantum effect in this nanometer device. The impact of high-k oxide gate is investigated and analyzed; the results confirm that the high-k is an interesting alternative to reduce tunneling gate current of the DGMOS transistor but reach the same drain one. Considering the oscillator, our goal is focused on the analysis of its phase noise. The Linear Time Variant (LTV) model of phase noise is considered. It is based on the Impulse Sensitivity Function (ISF) which describes carefully the sensitivity of an oscillator to a parasite impulse current injection in different nodes of the circuit. The obtained results pointed out that the ISF function is sinusoidal and its period is nearly the same of the oscillator output signal for different dielectric oxide. It also states that the phase noise of a Colpitts oscillator is not affected by the use of the high-k materials. Finally this method, if extended, is a good tool to investigate a perturbation response on such circuits

Modelling of parasitic effects induced by electrically active defects in a SiGe HBT

In this paper, we present a numerical modelling of a NPN SiGe heterojunction bipolar transistor (HBT) realized in an industrial 0.35 µm BiCMOS process, using our own software simulator “SIBIDIF”, taking into account some electrically active defects in the HBT device. The electric performances of this device can be penalized by the presence of defects inherent to the complex structure shrinking. For our devices, most of these relevant defects are located at the vertical interface between the spacers and the polysilicon emitter, due to the Reactive Ion Etching (RIE) process step. Nevertheless, their localization, as well as theirs effective density or their capture section, have an influence on the electric characteristics of the HBT's. As a check, we find some good agreement between our simulated results and some experimental ones. Our work is focused on the identification of defects responsible for the current fluctuations at the origin of low frequency noise or Random Telegraphic Signals in industrial submicronic BiCMOS technologies. Gummel characteristics are simulated in order to identify generation-recombination or trap assisted tunnelling process in the base current. We have shown that devices having an excess base current present random discrete fluctuations on the base current

Transient Solution Determination of the Boltzmann Equation Using a Polynomial Expansion

The transient and stationary Boltzmann equation are solved by using a Legendre-Laguerre polynomial expansion for p-Si. Its resolution technique is based on a least-square fitting algorithm. We show this method to be as accurate as the exact ones (particular or direct iterative process); the great interest lies on its fast computation, roughly 200 times faster than a monte-Carlo code for instance, for the same accuracy

Design of complementary LDMOS in 0.35

In this paper, an nLDMOS and a pLDMOS are developed by slight modifications of the base process steps of 0.35 μm BiCMOS technology. Extra two masks are used for the formation of the body region and the drift region with slightly added thermal budget and without resorting to high-tilt implants. The specific ON-resistance (RON,SP) and the OFF-state breakdown voltage (BV) are 1.5 mΩ cm2 and 60 V, for the nLDMOS and 3.0 mΩ cm2 and 160 V, for the pLDMOS, so the devices can typically be operated around 42 V supply voltage, which is suitable for the new automotive applications. An isolation mechanism between the power devices is suggested using a deep trench filled with silicon dioxide and undoped polysilicon. The polysilicon has a nearly perfect conformal deposition, that is, both step coverage and bottom coverage are 100%. A simple subcircuit model is built using a two module approach, one for the intrinsic MOS area and the other for the drift region. The Spice model parameters of the intrinsic MOS part are extracted using a system that links the ICCAP extraction tool with the results of the ISE-TCAD tools. The simulation results using the Spice model are compared to the results provided by ISE-TCAD tools, and the accuracy at room temperature is less than 5% for the whole voltage domain. An interface circuit, to convert 0/3.3 V to 0/42 V, suitable for automotive applications, is proposed

Design and characterization of high voltage devices integrated in a standard CMOS technology

A fully silicon CMOS compatible high voltage (H-V) integrated circuit has been developed that features 5-V high performance digital CMOS with H-V devices. The high voltage device has to support voltage drop upper 50 V between drain and source, both for NMOS and PMOS transistors. It will be placed only in the input and output circuit, for interface application. A lateral diffusion MOS (LDMOS) structure has been chosen, for its compatibility with 5 V CMOS devices. Two specific implants are introduced into the standard process. They create the high voltage N and P junctions. Numerical simulations are performed to determine specific implant characteristics. Moreover, a two-dimensional simulator gives best LDMOS dimensions. A process control monitor has been done according to these results. After the technological realization, a quantitative electrical characterization, as maximal breakdown voltage, determines the best architecture. These devices are modeled by the MOS SPICE2G Level3, which gives sufficient results for digital applications. A simple circuit, a 5 V-50 V buffer, is simulated, realized and characterized, to conclude this work

A NUMERICAL POWER IGBT MODEL AND ANALYSIS OF IMPROVING SUPPRESSION OF ITS LATCHING Presentation: Oral or Poster. Topics: Power Electronics or Electronics

Abstract During the last few years, great progress in the development of a new power semiconductor devices has been make the new generation of the power semiconductor is capable of conducting more current and blocking higher voltage that is the insulated gate bipolar transistor (IGBT). The aim of this paper, is to present a new approach which consists in defining our computer program (numerical model) of the IGBT based on the finite element technique (FEM), to offer an easy to use IGBT and other devices for our program, showing short computing time and reasonable accuracy, to predict and understand the behavior of various topologies of devices, to perform automated layout of the device to overcome some of the difficulties associated with analytical methods and to identify the failure mechanisms e.g. latch up, current redistribution limiting SOA, are know as the undesirable characteristics of IGBTs devices, then we propose some remedies. The validity of our computer program (this approach) is confirmed by comparison between simulation and theory results as well as the manufacture's data, and a good agreement is recorded for IGBT devices