Growth of thin Si oxide in a cyclic oxygen plasma environment below 200 °C

The growth of Si oxide by means of a cyclic radio-frequency (rf) plasma oxidation process has been explored in a low temperature range of 100-200 °C. The growth mechanism exhibits Cabrera-Mott (CM) oxidation, that is, the transport of mobile ionic species is assisted by an electric field. The low activation energy of 0.3 eV is attributed to the small size of O⁻ and the assistance of the electric field. The oxide becomes off-stoichiometric as one approaches to the exterior surface of the oxide layer.     

Ultraviolet photodissociation at 266 nm of phosphorylated peptide cations

Ultraviolet (UV) photodissociation (PD) experiments using 266 nm light were performed for a series of phosphopeptide cations in a Fourier transform mass spectrometer. The objective of the experiments was to determine whether 266 nm UV irradiation on the phosphopeptide cations would induce unique peptide backbone dissociation. In addition, the general behavior of the phosphate loss (?80 or ?98 Da) was monitored, particularly for those phosphopeptides with a phosphotyrosine residue that itself is a UV chromophore. For phosphopeptides with a UV chromophore, their photodissociation behavior was very similar to that of low‐energy sustained off‐resonance irradiation collisionally activated dissociation (SORI‐CAD), with a few exceptions. For example, b‐ and y‐type peptide backbone fragments were prevalent, and their dephosphorylation behavior was consistent with that of the SORI‐CAD results. For phosphoserine peptides, the loss of a phosphate group was always observed. On the other hand, for phosphotyrosine peptides, the phosphate loss was found to be dependent on the presence of a basic amino group in the sequence and the charge state of the precursor ions, in agreement with the CAD results in the literature. However, hydrogen atom loss or aromatic side chain loss, which is known to be the excited state specific fragmentation pathway, was rarely observed in our 266 nm UV PD experiments, in contrast to the previous UV PD literature (particularly at 220 nm). The mechanism for these observations is described in terms of dominant internal conversion followed by intramolecular vibrational energy redistribution (IVR). Copyright © 2009 John Wiley & Sons, Ltd.     

Frequency domain lifetime characterization

Time-based measurements are commonly used for lifetime characterization of semiconductors. We have developed the theory, verified by experiment, of frequency-based lifetime characterization as an alternative to time-based measurements for MOS devices biased in inversion. One consideration during lifetime/diffusion length measurements, is whether the near-surface space-charge region or the bulk or quasineutral region is characterized. To characterize the near-surface space-charge region of the device, one usually makes room temperature pulsed MOS capacitor or diode leakage current measurements. We show that room-temperature, frequency-domain capacitance, conductance, or resistance measurements characterize the quasineutral bulk, not the space charge region, in contrast to room-temperature pulsed MOS-C or diode leakage current measurements which characterize the space-charge region     

Compact stripline-fed meander slot antenna

A meander-type slot antenna fed by a stripline is proposed for use in miniaturised personal communication systems. By varying the slot configuration of the antenna, a 56% smaller antenna to substitute the conventional slot antenna is achieved. Simulated and measured results are presented     

Electromagnetic penetration into 2-D multiple slotted rectangularcavity: TM-wave

Electromagnetic wave penetration into the two-dimensional (2-D) rectangular cavity with multiple slots in an infinite conducting plane with a finite thickness is investigated. The Fourier transform and the mode-matching technique are used to obtain simultaneous equations, which are solved to represent the scattered and the penetrated fields in series forms that are suitable for numerical computations     

Measurement of multiperiod aggregative efficiency

This article proposes a new method for measuring an aggregative efficiency of multiple period production systems. Every organization or firm generates a time series of data that represent its performances in the resource utilization and output production over multiple periods, and often desires an aggregated measure of efficiency for several periods of interest. Data envelopment analysis (DEA) has become an accepted and well-known approach to evaluating efficiency performance in a wide range of cases. However, most of the DEA studies have dealt primarily with ways to gauge the efficiency of production in only a single period so this efficiency reflects the insufficient or partial performance of multiple period productions. The new method is developed through extensions of the concept of Debreu–Farrell technical efficiency and is applied to evaluating the efficiency of cable TV service units with 3-year data.     

SET/CMOS hybrid process and multiband filtering circuits

We have developed an integration technology for the single electron transistor (SET)/CMOS hybrid systems. SET and CMOS transistors can be optimized without any possible degradation due to mixing dissimilar devices by adopting just one extra mask step for the separate gate oxidation (SGOX). We have confirmed that discrete devices show ideal characteristics required for the SET/CMOS hybrid systems. An SET shows obvious Coulomb oscillations with a 200-mV period and CMOS transistors show high voltage gain. Based on the hybrid process, new hybrid circuits, called periodic multiband filters, are proposed and successfully implemented. The new filter is designed to perform a filtering operation according to the periodic multiple blocking bands of which a period is originated from the SET. Such a novel function was implemented efficiently with a few transistors by making full use of the periodic nature of SET characteristics.     

Surface structure of low-coveraged Cs on Si(0 0 1)-() system

Alkali metals (AM) on semiconductors have been investigated as a simple model system for the metal-semiconductor interfaces due to their simple electronic structures. Especially, cesium (Cs) on Si(0 0 1) surface has been studied with various experimental techniques. In this study, we investigated the atomic structure of initial Cs adsorption on Si(0 0 1)-(2×1) surface using coaxial impact collision ion scattering spectroscopy. When Cs atoms are adsorbed on Si(0 0 1)-(2×1) up to 0.2 ML at room temperature, the initial adsorption site is on-top T3 site with poor periodicity and the length of Si dimer is reserved as in the clean Si(0 0 1) surface. It is also found that Cs atoms adsorbed on Si(0 0 1) surface with a height of 2.83±0.05 Å from the second layer of Si(0 0 1) surface.