Semiconductor Devices Simulation

A New electrical method, using charge-pumping (CP) technique under bias thermal stress (BTS), has been described in this paper. This technique is based on the charge-pumping measurement which in turn used to extract the flat-band voltage before and after an applied bias voltage at high temperature. The obtained flat band voltage shift, that is due to redistribution of the mobile ionic charges, or to generation of the oxide trapped charge or both, may be used to determine their densities.

The dielectric properties of Au/(1 % graphene
doped-Ca1.9Pr0.1Co4Ox)/n-Si structures were investigated
by the impedance spectroscopy method including capacitance–
voltage (C–V) and conductance–voltage (G/x–
V) measurements in the frequency range of 10–2 MHz at
room temperature. The experimental results show that the
real and imaginary parts of dielectric constant (e0, e00) and
electric modulus (M0 andM00), and ac electrical conductivity
(rac) are a strong functions of frequency and voltage, both.
Negative dielectric constant behavior was observed at sufficiently
high forward bias voltages at low frequencies and it
was attributed to the interfacial polarization, interface traps
and series resistance. e0 decreases with increasing frequency
at sufficiently high biases whereas e00 increases. Since
interfacial polarization and interface states, both, can follow
the ac external signal easily at low frequencies, there occurs
a contribution to the measured capacitance and conductance.
The negative values of e0 correspond to maximum value of
e00. Such contrary behavior in the e0 and e00 appears as an
abnormality when compared to the conventional behavior
metal–semiconductor structures with and without interfacial
layer. Experimental results confirmed that the dielectric
properties of these structures are quite sensitive to the frequency and applied bias voltage, both, especially at low
frequencies and high voltages because of density distribution
of interface states and interfacial polarization.

Dr. Herbots, Belgian-born, Ph.D. graduate in applied physics of Catholic University of Louvain and a microelectronics specialist, made progress in the course of three years as an Oak Ridge Re- search Associate and four years as an MIT professor (1987-1991). At MIT she developed new methods for synthesizing thin film layers on chips at low temperatures, and for creating films that can’t be grown using thermal processes.

She joined Arizona State University in 1991,  to further develop a novel invention she had made at MIT. Called Combined Ion and Molecular Beam Deposition or CIMD, it is a  tech- nique for depositing materials on semiconductors that combines a so- phisticated evaporation system (molecular beam deposition) with an easily controlled ion beam.
But a life-threatening accident curtailed her research
After building a CIMD clean room at Arizona State University and getting research off to a good start, Nicole Herbot’s work, almost her life, came to an abrupt end in May 1994.  This is where the history of her research in ordered nanophases of SiO2 on Si(100) began. She had to rebuild her scientific understanding of matter,  interfaces, phase structures and nanophases after losing her short memory and developing "petit mal" (a milder form of epilepsy characterized by short or longer "absences" where the patient loses awareness of surroundings without loss of consciousness). The episodes increase with fatigue, mild illnesses and colds, to several a day.  They result in post-"absences" exhaustion, typical of epilepsy, where the patient needs to sleep for a period of time concomittant with the duration of the absences to recover.  The condition precludes driving.
The long hours spent on bed rest recovering from the petit mal absences gave her the time to reflect on the continuing mystery of SiO2/Si(100) extraordinary properties in microelectronics.  This is how her "Tsunami" model of structural collapse as Si(100) crystals oxidizes into an amorphous film came to be, and a new concept to prevent structure loss and thus grow heteroepitaxial SiO2 on Si(100) was conceived, and led to several patents (2003, 2010), PhD theses and papers.

Top-down method was used to fabricate zinc oxide (ZnO) nano wire field effect transistor (NWFET) biosensor. The nanosensor was used to measure the electrical characteristics of lysozyme (LYSO) and bovine serum albumin (BSA) protein solutions in phosphate buffered saline (PBS). The LYSO and BSA proteins are oppositely charged at measurement pH of 7.4. Subthreshold voltage shift of 340 mV and 700 mV due to surface charge effect on the device channel is obtained for the LYSO and BSA solutions respectively. A NWFET sensitivity of 72 % is achieved for the LYSO proteins while the BSA proteins resulted in a sensitivity of 98%.

A Mobile Ad-hoc Network (MANET) has a collection of numbers of wireless nodes which is each device in MANET having ability to free to move in any direction so that it is useful in all applications. In MANET nodes change position quite frequently, this means that we have need routing protocols that quickly adapts to topology changes. An ad-hoc network is self-organising and distributive in manner. The MANET is works as router so that linked with the other nearest devices. A mobile ad hoc network (MANET) is a wireless network follows the multiple hop routing instead of static network infra to provide network connectivity. Each device in a MANET is free to move independently in all direction freewaysand will therefore nodes change position in large networks all routing protocols. The routing protocols are needed for conveying information in Ad-hoc network there are various performance parameters to compare the Ad-hoc routing protocols. My area of interest in this paper to analyze the different performance parameters Recent research has focused on simulation studies with mobility and non-mobility scenarios to investigate and improve routing protocols. we have simulate the all three routing protocols in mobility as well as non-mobility scenario with nodes up to 300 also plot the graphs throughput, Delay, PDR, Dropping Ratio, and average energy consumption by using Network Simulator version 2.34.).

A New electrical method, using charge-pumping (CP) technique under bias thermal stress (BTS), has been described in this paper. This technique is based on the charge-pumping measurement which in turn used to extract the flat-band voltage before and after an applied bias voltage at high temperature. The obtained flat band voltage shift, that is due to redistribution of the mobile ionic charges, or to generation of the oxide trapped charge or both, may be used to determine their densities.

A Mobile Ad-hoc Network (MANET) has a collection of numbers of wireless nodes which is each device in MANET having ability to free to move in any direction so that it is useful in all applications. In MANET nodes change position quite frequently, this means that we have need routing protocols that quickly adapts to topology changes. An ad-hoc network is self-organising and distributive in manner. The MANET is works as router so that linked with the other nearest devices. A mobile ad hoc network (MANET) is a wireless network follows the multiple hop routing instead of static network infra to provide network connectivity. Each device in a MANET is free to move independently in all direction freewaysand will therefore nodes change position in large networks all routing protocols. The routing protocols are needed for conveying information in Ad-hoc network there are various performance parameters to compare the Ad-hoc routing protocols. My area of interest in this paper to analyze the different performance parameters Recent research has focused on simulation studies with mobility and non-mobility scenarios to investigate and improve routing protocols. we have simulate the all three routing protocols in mobility as well as non-mobility scenario with nodes up to 300 also plot the graphs throughput, Delay, PDR, Dropping Ratio, and average energy consumption by using Network Simulator version 2.34.).

This paper studies the effect of atomic layer deposition (ALD) temperature on the performance of top-down ZnO nanowire transistors. Electrical characteristics are presented for 10-μm ZnO nanowire field-effect transistors (FETs) and for deposition temperatures in the range 120°C to 210°C. Well-behaved transistor output characteristics are obtained for all deposition temperatures. It is shown that the maximum field-effect mobility occurs for an ALD temperature of 190°C. This maximum field-effect mobility corresponds with a maximum Hall effect bulk mobility and with a ZnO film that is stoichiometric. The optimized transistors have a field-effect mobility of 10 cm 2 /V.s, which is approximately ten times higher than can typically be achieved in thin-film amorphous silicon transistors. Furthermore, simulations indicate that the drain current and field-effect mobility extraction are limited by the contact resistance. When the effects of contact resistance are de-embedded, a field-effect mobility of 129 cm 2 /V.s is obtained. This excellent result demonstrates the promise of top-down ZnO nanowire technology for a wide variety of applications such as high-performance thin-film electronics, flexible electronics, and biosensing.

New dielectric materials based on SiGe have been formed at room temperature by direct ion beam oxidation and nitridation. Si0.8Ge0.2 layers were deposited by molecular beam epitaxy on Si(100) and then exposed to a low-energy ion beam of O-18-2+ to form oxides and N-14-2+ to form nitrides. The ion energies investigated ranged from 100 eV to 1 keV. Thin films of SiGe oxide and SiGe nitride were formed at all energies used as evidenced by in situ x-ray photoelectron spectroscopy analysis. They were found to be insulating by ex situ scanning electron microscopy observations. During the ion beam processing, the Ge content of the alloy layer decreases, due to preferential sputtering of Ge and the Ge compounds. However, as the ion energy is decreased, the concentration of Ge in the alloy remains closer to the original content. The thermal stability of these new SiGe dielectrics was also assessed up to 500-degrees-C.

We have developed a stochastic model of the resistive switching mechanism in resistive random access memory (RRAM) based on electron hopping. The distribution of electron occupation probabilities obtained with our approach is in good agreement with previous work. In particular, a low occupation region is formed near the cathode for bipolar switching behavior or near the anode for unipolar switching behavior. This result indicates that a decrease of the switching time with increasing temperature cannot be explained only by reduced occupations of the vacancies in the low occupation region, but is related to an increase of the mobility of the oxide ions. A hysteresis cycle of RRAM switching simulated with our stochastic model is in good agreement with experimental results.