Temperature measurement of metal-coated silicon wafers bydouble-pass infrared transmission

We report the measurement of the temperature of metal-coated silicon wafers by a double-pass infrared transmission technique. Infrared light incident on the backside of the wafer passes through the wafer, and is re-emitted out the backside after reflecting off the metal surface on the front side of the wafer. The temperature is inferred by the change in the re-emitted signal due to absorption in the wafer. The work has been demonstrated on double-polished wafers from 100°C to 550°C using wavelengths from 1.1 to 1.55 μm. A method for overcoming limitations of the present arrangement for wafers with a rough backside is proposed     

Diagnostics of rolling-element bearing condition by means of vibration monitoring under operating conditions

Many investigations have been made of the correlation of diagnostic parameters with stress and damage in rolling-element bearings. It was found that parameters normalised to zero conditions are more suitable for diagnostic purposes than time-dependent absolute values. A new superior diagnostic parameter can be simply determined.     

Detecting test set hardware degradation using statistical data modelling

In electronic device manufacturing, a significant amount of time is spent testing the product using sophisticated test sets. These test sets routinely develop hardware problems that cause disruption of the manufacturing process. This paper discusses how computerized networking of test sets can be used to systematically monitor and detect these hardware problems. A statistical methodology for modelling and analysing test set data is presented, along with a detailed specific example.     

25-nm p-channel vertical MOSFETs with SiGeC source-drains

The scaling of vertical p-channel MOSFETs with the source and drain doped with boron during low temperature epitaxy is limited by the diffusion of boron during subsequent side wall gate oxidation. By introducing thin SiGeC layers in the source and drain regions, this diffusion has been suppressed, enabling for the first time the scaling of vertical p-channel MOSFETs to under 100 nm in channel length to be realized. Device operation with a channel length down to 25 nm has been achieved     

Mothers' beliefs about the causes of infant growth deficiency: is there attributional bias?

Tested for defensive attributional bias in mothers' causal explanations for infant (2-12.5 months) growth deficiency. Mothers of healthy babies (controls; n = 82), growth deficient babies without medical problems (n = 27) and growth deficient babies with mild medical problems (n = 22) rated their levels of agreement with 23 causes of growth problems which were designed to vary in the degree of personal threat to parenting self-esteem. Ratings were completed for the mother's (Own) baby and for a nonspecific (Other) baby. Findings partially support a theory of defensive attributional bias, with higher agreement when causes referred to Other (vs. Own) baby, and lower agreement with family-related than with medical/nutritional causes. Factors that may have influenced material experience of threat and implications of the findings for clinical practice are discussed.     

Benefit of 6 months long-term physical training in polymyositis/dermatomyositis patients

OBJECTIVE: The benefit of long-term physical training in patients with chronic polymyositis or dermatomyositis (PM/DM) was studied prospectively. METHODS: Eight patients with chronic PM/DM participated in a training programme for 6 months. A group of five PM/DM patients without any physical training was observed for control purposes. RESULTS: While there was no significant change in serum creatine phosphokinase (CPK) levels, the 'activities of daily living (ADL)' score improved significantly (P < 0.03), peak isometric torque (PIT) generated by muscle groups in the lower extremities rose significantly (P < 0.03) and there was a statistically highly significant increase in peak oxygen uptake (VO2max) relative to body weight (P < 0.02) due to the long-term training. The patients improved their aerobic capacity by 28%, which is clinically significant. In the untrained patients, no improvement in these target parameters was observed. CONCLUSION: In clinically stable DM/PM patients, long-term physical training can safely be performed and is recommended as part of a comprehensive rehabilitation management, particularly in view of the cardiopulmonary risk in these patients.     

Growth pressure effects on Si/Si1−xGex chemical vapor deposition

We studied the effects of growth pressure on Si_1−xGe_x/Si heterostructures grown by rapid thermal chemical vapor deposition in the pressure range of 6–220 Torr. The material was characterized by photoluminescence (PL), x-ray reflectivity, and electrical measurements on resonant tunneling diodes (RTDs). High quality material was demonstrated throughout the pressure range, but a weaker PL intensity at higher pressure (220 Torr) indicates lower lifetimes. Interface abruptness was degraded at higher pressures due to gas transients. This was confirmed by x-ray reflectivity measurements and the performance of RTDs. We have established a low pressure limit to interface roughness of 0.2–0.5 nm, determined by x-ray reflectivity.     

Increased drain saturation current in ultra-thinsilicon-on-insulator (SOI) MOS transistors

Based on substrate-charge considerations, an increased drain saturation current for MOS transistors in ultrathin silicon-on-insulator (SOI) films is predicted, compared to similar transistors in bulk or thick SOI films. For typical parameters of 200-A gate oxide with a channel doping of 4×10¹⁶ cm^-3, the drain saturation current in ultrathin SOI transistors is predicted to be ~40% larger than that of bulk structures. An increase of ~30% is seen in measurements made on devices in 1000-A SOI films     

Numerical simulation of the temperature dependence of photoluminescence in strained-Si1−xGex/Si heterostructures

In previous work it has been shown that the decay in photoluminescence from Si/strained-Si_1–xGe_x/Si quantum wells at temperatures over 100 K is controlled by surface recombination and that the photoluminescence intensity can be increased by over an order of magnitude by surface passivation. These results had been explained only by a simple phenomenological model, which could not explain why at high pump power density the observed luminescence was constant from 77 to 250 K. This paper uses a two-carrier heterojunction device simulator to determine the carrier profiles during optical pumping. The profiles are used to understand quantitatively luminescence as a function of temperature and pump power density without making the over-simplifying assumptions required for analytical modeling. Surface recombination velocities over 10³ cm/s drastically affect the results, and Auger recombination plays an important role at high pump power density.     

Multi-view structure-from-motion for hybrid camera scenarios

We describe a pipeline for structure-from-motion (SfM) with mixed camera types, namely omnidirectional and perspective cameras. For the steps of this pipeline, we propose new approaches or adapt the existing perspective camera methods to make the pipeline effective and automatic. We model our cameras of different types with the sphere camera model. To match feature points, we describe a preprocessing algorithm which significantly increases scale invariant feature transform (SIFT) matching performance for hybrid image pairs. With this approach, automatic point matching between omnidirectional and perspective images is achieved. We robustly estimate the hybrid fundamental matrix with the obtained point correspondences. We introduce the normalization matrices for lifted coordinates so that normalization and denormalization can be performed linearly for omnidirectional images. We evaluate the alternatives of estimating camera poses in hybrid pairs. A weighting strategy is proposed for iterative linear triangulation which improves the structure estimation accuracy. Following the addition of multiple perspective and omnidirectional images to the structure, we perform sparse bundle adjustment on the estimated structure by adapting it to use the sphere camera model. Demonstrations of the end-to-end multi-view SfM pipeline with the real images of mixed camera types are presented.