A Fully-Automated Electron Beam Test System for VLSI Circuits

A fully automated, stroboscopic electrobeam test system that analyzes the behavior of logic VLSI circuits, this system consists of a stroboscopic electron-beam tester combined with an LSI CAD system. LSI circuit design data, read from the CAD system, provides a designed map. The host computer performs interconnection pattern recognition by superimposing this map onto an observed stroboscopic SEM image. Then, once the circuit nodes for voltage waveform measurements are automatically determined on the superimposed map. Next, the electron beam is positioned on the actual circuit-under-test wires. These automatic processes result in measured waveforms, which are displayed on the host computer terminal. This system has been applied to a 2.3K-gate logic LSI circuits, and has been successful in locating the critical path. This system, coupled with the recently developed fault diagnostic electron-beam tester, Finder, constitutes a unified electron-beam test system.     

Multiphase oscillator and multivibrator using improved unijunction transistors

The properties of multiphase oscillator and multivibrator using an improved unijunction transistor, fabricated by planar technology, were investigated. The 3-phase oscillator is very useful as the transfer pulse generator for recently developed c.c.d. and p.c.d. devices.     

Integrating an Electron-Beam System into VLSI Fault Diagnosis

Using design data, the system can prepare a logic-state map for the device under test. The map draws top-layer connections in different colors according to their expected logic states so the map may be compared to the DUT image observed by the electron-beam tester. The system has successfully tested a 75K-transistor VLSI device.     

Detection of left ventricular enlargement by electrocariography

Cardiomegaly is one of the commonest findings encountered in daily clinical practice, and its differential diagnosis is a common clinical problem. There are many electrocardiological (ECG) criteria known for left ventricular hypertrophy (LVH), but its limitations have also been suggested. We evaluated 102 patients fulfilling the ECG criteria of precordial and limb lead for LVH with echocardiographic findings as a gold standard. Among these 102 patients, the echocardiogram revealed 38 subjects with LVH, 26 subjects with left ventricular dilatation (LVD), 7 subjects with both findings, and 31 subjects with neither findings. Precordial criteria such as SV1+RV5 or RV6 > 30 mm, SV1 or SV2+RV5 > 35 mm, R+S > 40 mm, SV1 or SV2+RV5 or RV6 > 35 mm, SV2+RV4 or RV5 > 35 mm, high in sensitivity and low in specificity for LVD and LVH, are appropriate for screening LVD and LVH. Cornell limb lead criterion, SV3+RaVL > 28 mm (male), SV3+RaVL > 20 mm (female), high in sensitivity and specificity only for LVH, is the best elecrocardiographic criterion to evaluate LVH. Precordial and limb lead criteria such as R> 13 mm, RaVL > 12 mm, RaVF > 20 mm, onset of intrinsicoid deflection in V5 or V6> 0.05 sec, left axis deviation -30 degrees to -90 degrees, low in sensitivity, and high in specificity, are useful to rule out LVH and/or LVD. Our findings suggest LVD and LVH can be evaluated by ECG, but similar sensitivity and specificity for both LVH and LVD makes separation of LVH from LVD unattainable.     

Voltage-controlled negative resistance in conductance transistors with hook structure

Experimental results are presented wherein a conductance transistor with a hook structure (h.c.d.t.) has a voltage-controlled negative resistance. The I/V characteristic has practical merit, in that the current becomes nearly zero in the high-voltage region, so that it can be applied to various electronic switching circuits.     

Properties of Se-Ge inorganic photoresist as an ion-implantation mask

The usefulness of Se-Ge inorganic photoresists as ion-implantation masks is described. Experimentally determined values of the projected range and range straggling are in agreement with theory. The required masking thickness is shown to be about ? of that of organic photoresist. Other advantageous features are also pointed out.     

Voltage-controlled negative resistance in a submicron vertical JFET

A conspicuously sharp voltage-controlled negative resistance (NR) has been observed in a scaled-down, sub-micron vertical JFET. This JFET has a “surface-electrode” structure in which both source and gate layers lie only on the surface of the silicon substrate. Source layer size is 0.6 × 0.6 μm, and gate-source spacing is 0.2 μm. The present JFET has been fabricated with a self-aligning process employing a novel amorphous material, SiGeB ternary alloy.In order to obtain a condition in which NR occurs, two-dimensional computer simulation has been carried out. This simulation has shown that conditions necessary for NR are also appropriate for high-speed operation of a scaled-down bipolar-mode JFET. A logic gate configuration taking advantage of this negative resistance has been devised.     

Evaluation of chemicals to control the generation of malodorous hydrogen sulfide in waste water

The effect of hydrogen peroxide, sodium/calcium hypochlorite and ferrous/ferric salts on hydrogen sulfide dissolved in waste water were investigated to establish an effective odour control system for Kuwait Sewage Networks. The waste water samples were collected from the inlet structure of main pumping station with pressure pipelines and analyzed for dissolved sulfide and pH before and after addition of chemicals individually and in combination under controlled laboratory conditions. The waste water contained dissolved sulfide in the range of 18 to 25 mg/l and pH ranged between 7.2 and 7.8. Various concentrations of above mentioned chemicals were tried to determine the accurate chemical requirement for oxidation or precipitation of dissolved sulfide in waste water. The reaction temperature was maintained at 35°C (±2°C), the normal temperature of waste water in Kuwait during summer. To oxidize 1 g of sulfide 1.25, 2.0 and 1.8 g hydrogen peroxide, sodium hypochlorite and calcium hypochlorite were required respectively. To remove 1 g of sulfide by precipitation with ferrous sulfate and ferric salt solution, 8 g and 4 g ferrous and ferric salt were required respectively under laboratory investigations. A combination of sodium hydroxide and sodium hypochlorite was also studied to control malodorous hydrogen sulfide in waste water. The addition of sodium hydroxide with sodium hypochlorite in waste water reduced the demand of hypochlorite 50%. This procedure was found to be cost effective and best suited for the warm climate of Kuwait and was implemented in the field at a screw conveyor type lifting station with gravity sewer pipelines. When sodium hypochlorite was injected without shock loadings of sodium hydroxide 46% reduction of dissolved sulfides was recorded and it was increased to 57% with shock loadings of sodium hydroxide, though the quantity of sodium hypochlorite was reduced to half than the former case. Similarly, 45 and 70% reduction in the emission of gaseous hydrogen sulfide was recorded with NaOCl injection without and with NaOH shock loading respectively. The cost comparison of all the chemicals when applied in field is also presented.