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Studies of implant activation in InAs have not been reported presumably because of challenges associated with junction leakage. The activation of 20 keV, Si+ implants into lightly doped (001) p-type bulk InAs performed at 100 °C as a function of annealing time and temperature was measured via Raman scattering. Peak shift of the L+ coupled phonon-plasmon mode after annealing at 700 °C shows that active n-type doping levels ≈5×1019cm–3 are possible for ion implanted Si in InAs. These values are comparable to the highest reported active carrier concentrations of 8–12×1019cm–3 for growth-doped n-InAs. Raman scattering is shown to be a viable, non-contact technique to measure active carrier concentration in instances where contact–based methods such as Hall effect produce erroneous measurements or junction leakage prevents the measurement of shallow n+ layers, which cannot be effectively isolated from the bulk. [ABSTRACT FROM AUTHOR]

Here, we have explored the thermal stability of α-(Al,Ga)2O3 grown by the molecular-beam epitaxy on m-plane sapphire under high-temperature annealing conditions for various Al compositions (i.e., 0%, 46%, and 100%). Though uncapped α-Ga2O3 undergoes a structural phase transition to the thermodynamically stable β-phase at high temperatures, we find that an aluminum oxide cap grown by atomic layer deposition preserves the α-phase. Unlike uncapped α-Ga2O3, uncapped α-(Al,Ga)2O3 at 46% and 100% Al content remain stable at high temperatures. We quantify the evolution of the structural properties of α-Ga2O3, α-(Al,Ga)2O3, and α-Al2O3 and the energy bandgap of α-Ga2O3 up to 900 °C. Throughout the anneals, the α-Ga2O3 capped with aluminum oxide retains its high crystal quality, with no substantial roughening. [ABSTRACT FROM AUTHOR]

In this paper, we report the systematic investigation on the melt characteristics of silicon during laser thermal processing (LTP) of amorphous silicon (a-Si) gates on ultrathin gate oxides. LTP is used to reduce the gate depletion effect in advanced semiconductor devices. The influence of implantation-induced damage and chemical inhomogeneities on the melt behavior of ion-implanted a-Si is studied using in situ time-resolved reflectance (TRR) measurements and ex situ secondary ion mass spectrometry. The results from TRR measurements indicate the presence of a buried melt for a-Si implanted with B+ at a subamorphizing dose. In contrast, such a melt behavior is not observed during LTP of undoped a-Si and a-Si implanted with As+ at an amorphizing dose. We attribute the marked difference in the melt characteristics to the competitive effects between compositional inhomogeneities and the extent of amorphization in the a-Si layer. It should be noted that the as-deposited a-Si gate is not really “amorphous” in the sense of an ion beam-induced amorphous layer. This postulation is verified by the absence of a buried melt in a-Si films implanted with Si+ prior to B+ implantation, where the dose of the Si+ implant is sufficient to cause amorphization in silicon and the amorphization depth greatly exceeds the projected range of the boron implant. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Studies the infrared absorption and Raman scattering intensity of the local carbon mode in Si1-yCy alloys. Growth by direct carbon implantation followed by different recrystallization procedures; Agreement with an extrapolation of the calibration curve; Evidence for the achievement of substitutionality in laser-recrystallized films.

The effect of a thermally grown silicon nitride (SiN[sub x]) film on end-of-range extrinsic dislocation loops in a silicon substrate was investigated by transmission electron microscopy. A layer of extrinsic dislocation loops was formed by annealing a Si wafer amorphized by a Ge[sup +] ion implant. A nitride film was grown on the Si by further annealing in ammonia (NH[sub 3]) at 810 and 910 °C for 30–180 min. Wafers with a loop layer were also annealed in argon (Ar) at the same conditions as the NH[sub 3]-annealed wafers to determine loop behavior in an inert environment. Samples annealed in NH[sub 3] had a significant decrease in the net number of interstitials bound by the loops, while those annealed in Ar showed no change. The results are explained by a supersaturation of vacancies caused by the presence of the nitride film, resulting in loop dissolution. By integrating the measured vacancy flux over the distance from the nitride/Si interface to the loop layer, we extract an estimate for the relative supersaturation of vacancies at 910 °C, C[sub V]/C∗[sub V]∼4, where C[sub V] is the concentration of vacancies and the asterisk denotes equilibrium. We rule out interstitial undersaturation-induced loop dissolution based on loop stability with temperature and oxidation-enhanced loop growth calculations. A comparison with estimated C[sub V]/C∗[sub V] values from a previous report using the same processing equipment and parameters but monitoring the change in Sb diffusivity with nitridation shows excellent agreement. [ABSTRACT FROM AUTHOR]

Provides information on a study which examined the non-equilibrium carbon-silicon alloys produced by laser induced epitaxy from ion implanted silicon. Epitaxial crystallization of carbon-silicon alloys; Application of pulsed laser in epitaxial crystallization; Use of transmission electron microscopy and infrared spectroscopy in analyzing carbon-silicon alloys.

Provides information on a study that examined the solidification of silicon-arsenic alloys induced by pulsed-laser melting at regrowth velocities where the partition coefficient is close to unity. Experimental techniques; Data analysis; Results and discussion on the study; Conclusions.

Measurements of liquid-phase diffusion coefficients for dilute tungsten and molybdenum in molten nickel were made using a pulsed ion-beam melting technique. A high-intensity beam of nitrogen ions is focused on the surface of a nickel substrate that was implanted with known concentration profiles of W and Mo. Melting of the surface to a depth of ∼1 µm allows broadening of the implant profiles while molten. Solute concentration-depth profiles were determined before and after melting using Rutherford backscattering spectrometry. Using a series of numerical simulations to estimate the melt history and diffusional broadening for mean liquid temperatures in the range 1755 to 2022 K, an effective diffusion coefficient is determined in each case by comparison to the measured depth profiles. This is found to be (2.4 ± 0.2) x 10-5 cm²/s for W and (1.6 ± 0.4) x 10-5 cm²/s for Mo, with an additional systematic uncertainty of ±0.5 x 10-5 due to instrumental and surface effects. [ABSTRACT FROM AUTHOR]

ABSTRACTBackgroundInduction of labor is carried out in approximately 20% of pregnancies. However, approximately 20% of women having induction of labor end up having a Cesarean delivery. The traditional method of predicting whether an induced labor will result in successful vaginal delivery is based on the preinduction ‘favorability’ of the cervix as assessed by the Bishop score. However, this assessment is subjective and several studies have shown a poor predictive value for the outcome of induction. ObjectivesTo examine the relationship between preinduction sonographically measured cervical length and the Bishop score and to compare the two measurements in the prediction of successful vaginal delivery within 24 h of induction. MethodsIn this multicenter study, preinduction cervical assessment was undertaken in 240 women with singleton pregnancies at 37–42 weeks of gestation. The Bishop score was assessed by digital examination and the cervical length was measured by transvaginal sonography. ResultsMultiple regression analysis demonstrated that cervical length, Bishop score and parity provided independent contribution in the prediction of the likelihood of delivering vaginally within 24 h. Further examination of the different components of the Bishop score showed that only cervical length provided a significant contribution in the prediction of the likelihood of vaginal delivery within 24 h. In the receiver operating characteristic curves, the best cut-off point for the prediction of successful induction was 28 mm for cervical length and 3 for the Bishop score. However, cervical length appears to be a better predictor than the Bishop score, with a sensitivity of 0.87 and a specificity of 0.71 compared to 0.58 and 0.77, respectively. Similarly, the Kaplan–Meier survival curves indicate that better discriminatory results in the prediction of vaginal delivery within 24 h are achieved using cervical length rather than the Bishop score. ConclusionTransvaginal sonographic measurement of cervical length provides a useful prediction of the likelihood of vaginal delivery within 24 h of induction. [ABSTRACT FROM AUTHOR]

In this letter, we report on the complex solidification structures formed during laser irradiation of a titanium nitride/titanium/polycrystalline silicon/silicon dioxide/silicon film stack. Due to enhanced optical coupling, the titanium nitride/titanium capping layer increases the melt depth of polycrystalline silicon by more than a factor of 2. It is found that the titanium atoms diffuse through the entire polycrystalline silicon layer during irradiation. Contrary to the expected polycrystalline silicon growth, distinct regions of polycrystalline and amorphous silicon are formed instead. Possible mechanisms for the formation of these microstructures are proposed. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article by Gareth Iacobucci which discussed NHS 111 and equivalent telephone advice services.

An abstract of the research paper "Placental Morphology and Fetal Renal Function: Is There a Relationship?," by M.O. Thompson and colleagues is presented.

Objectives: A preliminary assessment of the usefulness of a non-Doppler technique of uterine artery blood flow measurement in twin pregnancy, for the prediction of preeclampsia, utero-placental insufficiency and intrauterine growth restriction. To compare the results obtained with the contemporary Doppler method. Methods: A prospective study of 32 twin pregnancies presenting consecutively for a routine second trimester ultrasound scan. Maternal demographic and physical characteristics were recorded in all cases. Using previously described methods, blood flow studies were then conducted using the two different techniques; pulsed color Doppler was used to measure blood flow velocity waveform resistance indices, while a time domain correlation technique with color M-mode imaging was used to measure blood volume flow in both uterine arteries. The placental site and morphology, uterine artery waveform characteristics, and presence or absence of diastolic notches were recorded. The ultrasound fetal growth measurements were plotted on reference charts to assess individual fetal growth patterns, and the obstetric outcomes were recorded for all the pregnancies. Statistical analysis was performed to assess the predictive value of each method of blood flow measurement for the relevant obstetric complications. Exclusions: One mother with sickle cell trait (Hb A + S). Results: An abnormal uterine artery waveform (high resistance with persistence of uterine artery notching) was of limited value in the prediction of pre-eclampsia and IUGR in twin pregnancies. There was close correlation between a significant reduction in uterine artery blood volume flow and early onset intrauterine growth restriction requiring delivery before 34 weeks gestation. Uterine artery blood volume flow may be less influenced by the placental site compared with traditionally used resistance and pulsatility indices. Conclusions: Uterine artery notching appears to be of limited value in the direct... [ABSTRACT FROM AUTHOR]

Study objectives: To evaluate the three commonly used indices of Doppler blood flow resistance in clinical practice for the uterine artery. By assessing the measures of central tendency, dispersion, and variation, to determine the most appropriate index for clinical use transabdominally in the second half of pregnancy. Methods: A prospective study of uterine artery Doppler measurement in singleton pregnancies between 18 and 32 weeks gestation. Using previously described methods, two independent measurements were obtained transabdominally from each side in all subjects. The systolic/diastolic ratio (SD ratio), pulsatility index (PI), and resistance index (RI) were recorded from both the right and left uterine artery in turn. All measurements were obtained by a single operator (MOT) using the same machine (Philips SD 800). The results were analyzed statistically for the measures of dispersion, distribution, and the variation explained. Results: There were 1796 observations from 449 subjects in total, with the SD ratio showing the widest dispersion. The PI measurements were intermediate with respect to both, while the RI showed the least dispersion. The RI distribution was the closest to a naturally distributed (Gaussian) pattern, followed by the PI. The SD ratio did not appear to conform to a normal distribution. The interquartile ranges (IRQ) for the SD ratio were 0.71, 0.73 (left- and right-uterine artery, respectively); PI: 0.42, 0.41; and RI: 0.15, 0.17. The mean of three derived measurements of the RI was sufficient to account for over 99% of the observed variation. Conclusions: Differences reported between the different resistance and pulsatility Doppler indices could be due to either random or systematic error, or a combination of both. The observations from this study suggest that when the RI is used, these are kept to a minimum. These findings may be helpful in selecting the appropriate index for uterine artery Doppler screening and clinical applications... [ABSTRACT FROM AUTHOR]