A low cost and low power silicon npn bipolar process with NMOS transistors (ADRF) for RF and microwave applications

A silicon bipolar process for RF and microwave applications, which features 25-GHz double-polysilicon self-aligned npn bipolar transistors with 5.5-V BV/sub CEO/, optional 0.7-/spl mu/m (L/sub eff/) NMOS transistors with p/sup +/ polysilicon gates for switch applications, lateral pnp transistors, high and low valued resistors, p/sup +/ polysilicon-to-n/sup +/ plug capacitors, and inductors is described. The npn transistors utilize nitride-oxide composite spacers formed using sacrificial TEOS spacers, a process which is simpler than the previously reported composite spacer processes. Use of the composite spacer structure virtually eliminates problems relating to the extrinsic-intrinsic base link-up and reduces plasma induced damage associated with the conventional spacer process. Microwave and RF capabilities of the process up to several GHz are demonstrated by fabricating and characterizing RF amplifiers, low noise amplifiers, and RF switches.<>     

Where did the Chili Get its Spice? Biogeography of Capsaicinoid Production in Ancestral Wild Chili Species

The biogeography of pungency in three species of wild chili in the chaco and surrounding highland habitats of southeastern Bolivia is described. We report that Capsicum chacoense, C. baccatum, and C. eximium are polymorphic for production of capsaicin and its analogs, such that completely pungent and completely nonpungent individuals co-occur in some populations. In C. chacoense, the density of plants and the proportion of pungent plants increased with elevation. Above 900 m, all individuals in all populations except two were pungent; nonpungent individuals in at least one of the two polymorphic populations were likely a result of spreading by humans. The occurrence of pungent and nonpungent individuals in three species of ancestral Capsicum and the geographic variation of pungency within species suggest that production of capsaicin and its analogs entails both costs and benefits, which shift from one locality to another. Determining the selection pressures behind such shifts is necessary to understand the evolution of pungency in chilies.     

A Study of Tricresyl Phosphate as an Additive for Boundary Lubrication

A method of combining thin-layer chromatography with activation analysis to measure quantitatively the individual impurities in tricresyl phosphate (TCP) is described. The relative amounts and types of impurities found in commercial grades of TCP are discussed. Preparative thin-layer chromatography and iron powder chromatography are applied to produce TCP samples with known concentrations of several impurities. The use of the four-ball wear tester as a method of determining trends in wear values as a function of base stock and additive quality is demonstrated. The relationship of acid phosphate rather than TCP concentration to antiwear properties of compounded lubricants is suggested by transition load studies.     

Preparations for Y2K: Revisiting the Behavioral Component of the Third-Person Effect

Although the behavioral component was an integral part of the original formulation of the third-person effect hypothesis, little research has examined the impact of biased media effect perceptions on behaviors that assume others have already been affected. The present study examines how third-person perceptions (the belief that other people are particularly vulnerable to media messages) contributed to intentions to prepare for problems stemming from Y2K, also known as the "millennium bug." Analyses using data from 2 regional probability samples taken in late 1999 show that perceptions about the potential effects of news messages influenced public anxiety about the Y2K situation and beliefs that other people would overprepare for the new year. These 2 variables, in turn, predicted intentions to stockpile supplies of food, water, gasoline, and cash. The article discusses the implications of these findings for understanding the relationship between perceptions of media effects and an extended range of behaviors.     

PMOS transistors fabricated in large-area laser-crystallised Si on silica

PMOS transistors have been fabricated in device-worthy Si which was achieved by large-area laser-crystallisation of Si on silica. The crystallised Si contains few large-angle grain boundaries due to laser-beam inhomogeneity but exhibits subgrain boundaries aligned along the laser track. Cracking of the Si, a result of the mismatch of the thermal expansion coefficients of Si and silica, has been substantially reduced by removing only a stripped region of the SiO2 encapsulation layer for transistor fabrication. A high yield and good electrical characteristics of the devices were obtained.     

Linear Delta Modulator Integrated Circuit with 17-Mbit/s Sampling Rate

Delta modulation (DM) is an attractive method of analog-to-digital (A/D) conversion in applications where simple and economical designs must be realized without sacrificing conversion quality. This paper describes a new single-chip, bipolar integrated circuit delta modulator that maintains a high conversion resolution over a wide range of sampling frequencies and ambient conditions. Its high-speed operation (maximum sampling rates greater than 15 Mbit/s) is achieved with lower power requirements than with comparable discrete realizations. Low sensitivities to power supply and ambient temperature variations, achieved with a novel logic design, make this circuit useful in a telephone switching office environment and as a buildlng block for other linear and companded analog-to-PCM converters.     

如何在全球经济风暴下持续茁壮成长

2009年对于半导体产业来说，将会是一个具挑战性的一年。半导体产业协会（SIA）预估半导体产业的营收将下降5．6％。信用紧缩将导致消费者集中于购买高价值的产品，而企业体将集中于购买应付紧急需求的设备。