JFET integration using a foundry SOI photonics platform

We explore the monolithic integration of conventional electronics with SOI photonics using the commercial silicon photonics foundry technology offered by A*STAR's Institute of Microelectronics (IME). This process offers optical waveguide modulators and photodetectors, but was not intended to support transistors. We present the implementation of junction field effect transistors (JFETs) integrated with optical waveguides and photodetectors. A simple SPICE model is developed for the JFETs based on the available ion implant parameters, and the geometry feature size allowed by the technology's layout rules. We have demonstrated the monolithic integration of photonics and electronics circuits. This work could be useful for application in waveguide sensors and optical telecommunications

AMBIVALENT IMPLICATIONS OF HEALTH CARE INFORMATION SYSTEMS: A STUDY IN THE BRAZILIAN PUBLIC HEALTH CARE SYSTEM

This article evaluates social implications of the ""SIGA"" Health Care Information System (HIS) in a public health care organization in the city of Sao Paulo. The evaluation was performed by means of an in-depth case study with patients and staff of a public health care organization, using qualitative and quantitative data. On the one hand, the system had consequences perceived as positive such as improved convenience and democratization of specialized treatment for patients and improvements in work organization. On the other hand, negative outcomes were reported, like difficulties faced by employees due to little familiarity with IT and an increase in the time needed to schedule appointments. Results show the ambiguity of the implications of HIS in developing countries, emphasizing the need for a more nuanced view of the evaluation of failures and successes and the importance of social contextual factors

NONINJECTING, HIGH-BARRIER JUNCTIONS ON p-TYPE SILICON.

The fabrication of junctions with very low minority-carrier injection ratios and reasonably good diode characteristics on p-type silicon is reported. These junctions were formed by growing an ultrathin oxide layer on a monocrystalline substrate, depositing polysilicon heavily doped in situ with phosphorus over the oxide, overlaying the polysilicon with aluminum, and then annealing the resulting sandwich structure at temperatures in the range 400-450 degree C. The junctions can exhibit leakage current densities below 10** minus **6 A multiplied by (times) cm** minus **2 at m

A Polysilicon Emitter Solar Cell

A new solar cell structure is reported in which the emitter consists of a thin layer of in situ phosphorus-doped polysilicon deposited by a low-pressure chemical vapor deposition (LPCVD) tehniques. The highest process temperature required to fabricate this structure is only 627 °C. Although the use of a polysilicon emitter results in some degradation in blue response, both theoretical and experimental results are presented indicating that photocurrent densities in excess of 30 mA cm 2 are attainable under AM1 illumination. The low back-injection current associated with the polysil

A floating gate mosfet dosimeter requiring no external bias supply

MOSFET dosimeters incorporating an electrically floating polysilicon gate have been fabricated in a commercial CMOS technology. Charge is placed on the floating gate by tunnelling from a small overlapping injector gate. Subsequent irradiation partially discharges the floating gate, producing a change in threshold voltage which can be used to infer the absorbed dose. No external power source is required during this sensing period. Sensitivities up to 70 mVGy-1 (0. 7 mV/rad) have been obtained for temperature-compensated matched-pair dosimeters under 60Co gamma irradiation

Effect of annealing on polysilicon emitter transistors

The effect of 900°C furnace annealing on transistors with in situ phosphorus-doped polysilicon emitters has been investigated. For devices with chemically grown interfacial oxides, annealing is essential to give acceptable emitter resistance and emitter Gummel numbers. For devices lacking an intentionally grown interfacial oxide, annealing is necessary to reduce the emitter resistance to a tolerable level, but it simultaneously lowers the emitter Gummel number

A method for contact resistivity measurement using thick, uniformly doped substrates

A method for measuring contact resistivity ρ{variant}c which makes use of thick, uniformly doped semiconductor samples is presented. The contacts take the form of parallel stripes which extend across the width of the sample, producing a two-dimensional current distribution. Conformal mapping is used to relate the resistance measured between the stripes to ρ{va

Bounds on bipolar transistor base transit time

The paper provides upper and lower bounds on the base transit time of a bipolar transistor which hold regardless of the shape of the base doping profile. These bounds apply, for the case of conventional bipolar transistors, when both the diffusion coefficient of the mobile carriers and the effective bandgap narrowing depend on doping density. They would also apply to composition grading in heterojunction bipolar transistors