Historically speaking, the world of extremely low-noise solid-state amplification has been dominated by exotic technologies such as InP and GaAs HEMTs. By cryogenically cooling these devices, it is possible to realize microwave amplifiers with noise temperatures as low as 5K over decades of bandwidth. Although HEMTs can provide very low noise amplification when cooled to cryogenic temperatures, their radiometer performance is limited by intrinsic transconductance fluctuations. It is believed that bipolar devices do not suffer from this problem. As industry has invested more and more money into silicon based technologies, silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) have continued to improve and are now at the point where they are beginning to become competitive with InP HEMTs for microwave cryogenic low-noise amplifiers. Although extremely high frequency device operation has been observed at cryogenic temperatures, little work has been done on modeling the noise of cooled SiGe HBTs. In this report, a thorough investigation into the theoretical and practical aspects of using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) for extremely low-noise applications is presented. The dissertation is broken up into three sections: 1) Background information: The fundamentals of SiGe HBTs are presented along with a discussion of how the properties of semiconductors change at cryogenic temperatures, as well the impact that these changes have on the performance of the devices. 2) Modeling: A comprehensive study of seven state-of-the-art HBTs at temperatures ranging from 18 K to 300 K is presented. The devices are compared in terms of dc, small-signal, and noise performance, and small-signal noise models are extracted. The section concludes with a brief summary of the important conclusions regarding the performance of SiGe devices at cryogenic temperatures. 3) Applications: The models developed previously are applied to the design of several state-of-the-art LNAs in both MMIC and discrete form. Noise performance better than 2 K is achieved in the low-GHz range, which is comparable to the best InP results. The section concludes with a discussion of some high-impedance differential amplifiers which have recently been fabricated.

Silicon-Germanium Heterojunction Bipolar Transistors for Extremely Low-Noise Applications

El trabajo desarrollado en esta Tesis se focaliza en el estudio de mecanismos de transporte electrico involucrados en la degradacion y eventual ruptura de peliculas dielectricas (oxidos delgados). Estos forman parte de una infinidad de dispositivos que son fabricados en vistas de posibles aplicaciones tecnologicas. El estudio de la degradacion adquiere relevancia debido a que es preciso saber como se degrada cada componente y como ello incide en el comportamiento electrico general del dispositivo. Las estructuras estudiadas consisten en apilamientos metal/ oxido/ semiconductor (del ingles MIS) que pueden ser pensados como capacitores y que, en particular, constituyen la estructura basica para la construccion de transistores de efecto campo (MOSFET, segun su sigla en ingles). A su vez, la misma estructura se encuentra presente en otro tipo de dispositivo con que se trabajo: las NROM (Nitride Read-Only Memories); que constituyen un tipo particular de las ampliamente difundidas memorias FLASH. Se trata de apilamientos fabricados a nivel comercial que se emplean actualmente como memorias no volatiles. Ademas, en la misma linea de analizar propiedades electricas de oxidos bajo distinto tipo de estimulos, se incursiono en el estudio de estructuras metal/ aislante/ metal (del ingles MIM). En ellas, la conmutacion resistiva se muestra como una de las posibles aplicaciones de algunos de los mismos oxidos mencionados con anterioridad. Complementariamente, se analiza la factibilidad de su uso como mecanismo de memoria, en comparacion con los mencionados NROM. El trabajo consistio en la caracterizacion electrica, comprension de los mecanismos de conduccion y/o conmutacion asi como el estudio bajo condiciones de degradacion tales como radiacion (de fotones , de iones pesados, protones y rayos X) y operacion prolongada (procesos de estres electrico). Si bien las distintas estructuras provienen de diversas colaboraciones con otros grupos de investigacion, tambien se efectuaron algunas incursiones en los procesos de fabricacion. Este trabajo comienza con la descripcion de los efectos producidos por la incidencia de distintos tipos de radiacion en estructuras MIS (metal/ aislante/ semiconductor), a partir de un analisis comparativo. Complementariamente, en los mismos apilamientos, se estudio la degradacion debida a la aplicacion prolongada de un voltaje. Luego se presenta un estudio orientado a comprender si la descarga producida por rayos X incidiendo en estructuras MOSFET condiciona la persistencia de las cargas atrapadas en las cercanias del dato perdido. A continuacion, la incursion en estructuras de tipo MIM dio lugar a una serie de indagaciones vinculadas con el topico de la conmutacion resistiva. Se vera que muchas de las tecnicas y aprendizajes adquiridos, durante los estudios precedentes, resultaron ventajosos al momento de encarar esta linea. Se puso de manifiesto la conmutacion resistiva en muestras basadas en MgO y HfO2. En el primer caso, una conmutacion entre estados muy disimiles (en orden de magnitud de la corriente) sugirio la propuesta de alternativas de fabricacion. En el segundo, una amplia variedad de experimentos fueron empleados con la finalidad de comprender el comportamiento evidenciado por dicho material, que resulto destacarse por la particularidad de sus propiedades (autolimitacion de corriente, ausencia de electroformado, resistencia al estres electrico, etc.).

/pdf/oxidos-delgados-para-micro-y-nanoelectronica-degradacion-z90ibyav99.pdf

Oxidos delgados para micro y nanoelectrónica: degradación, ruptura y aplicaciones tecnológicas

Publisher Summary
In many Silicon (Si) devices applications, electronic components and circuits are exposed to a hostile radiation environment. The kind of particles, their energy, and their spectral distribution impinging on a Si device strongly depend on the application field. In nuclear research and events, high energetic neutrons and photons are primarily released. For many satellite applications, protons and other charged particles (electrons) are predominantly present in the radiation belts, which are generated by solar flares and subsequently trapped in Earth's magnetic field. The chapter discusses some fundamental aspects related to the two basis mechanisms involved in radiation damage in semiconductor devices, i.e., ionization damage and displacement damage. Charge ionization affects the reliability of the insulators used in metal-oxide–semiconductor (MOS) transistors and charged coupled devices (CCDs). Charges become trapped in the oxide, shifting the flat-band voltage, and consequently the threshold voltage, which provokes electrical failure of electronic circuits and reduction of the operating lifetime. The degradation of solid-state components by displacement damage is a complex function of the original vacancy–interstitial pairs created. The latter can be modeled accurately by analytical procedures. The ultimate goal of these modeling efforts is to be able to simulate the expected damage in a given radiation and shielding environment, which replace timely and expensive radiation testing. This chapter discusses several measures for hardening metal-oxide–semiconductor (MOS) based technologies, especially for low-temperature applications.

Chapter 4 – Radiation Effects and Low-Frequency Noise in Silicon Technologies

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

C. Claeys

Author Tools

Chat about Author

Papers

Chapter 4 – Radiation Effects and Low-Frequency Noise in Silicon Technologies