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Gate Dielectric
A gate dielectric is a dielectric used between the gate and substrate of a field-effect transistor (such as a MOSFET). In state-of-the-art processes, the gate dielectric is subject to many constraints, including: * Electrically clean interface to the substrate (low density of quantum states for electrons) * High capacitance, to increase the FET transconductance * High thickness, to avoid dielectric breakdown and leakage by quantum tunneling. The capacitance and thickness constraints are almost directly opposed to each other. For silicon-substrate FETs, the gate dielectric is almost always silicon dioxide (called "gate oxide"), since thermal oxide has a very clean interface. However, the semiconductor industry is interested in finding alternative materials with higher dielectric constants, which would allow higher capacitance with the same thickness. History The earliest gate dielectric used in a field-effect transistor was silicon dioxide (SiO2). The silicon and silicondioxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric
In electromagnetism, a dielectric (or dielectric medium) is an Insulator (electricity), electrical insulator that can be Polarisability, polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of Polarisation density, dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly Chemical bond, bonded molecules, those molecules not only become polarised, but also reorient so that their Symmetry axis, symmetry axes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Oxidation
In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer. The technique forces an oxidizing agent to diffuse into the wafer at high temperature and react with it. The rate of oxide growth is often predicted by the Deal–Grove model. Thermal oxidation may be applied to different materials, but most commonly involves the oxidation of silicon substrates to produce silicon dioxide. The chemical reaction Thermal oxidation of silicon is usually performed at a temperature between 800 and 1200 °C, resulting in a so-called High Temperature Oxide layer (HTO). It may use either water vapor (usually UHP steam) or molecular oxygen as the oxidant; it is consequently called either ''wet'' or ''dry'' oxidation. The reaction is one of the following: :\rm Si + 2H_2O \rightarrow SiO_2 + 2H_ :\rm Si + O_2 \rightarrow SiO_2 \, The oxidizing ambient may also contain several percent of hydrochloric acid (HCl). The chlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egyptian Inventions
''Egyptian'' describes something of, from, or related to Egypt. Egyptian or Egyptians may refer to: Nations and ethnic groups * Egyptians, a national group in North Africa ** Egyptian culture, a complex and stable culture with thousands of years of recorded history ** Egyptian cuisine, the local culinary traditions of Egypt * Egypt, the modern country in northeastern Africa ** Egyptian Arabic, the language spoken in contemporary Egypt ** A citizen of Egypt; see Demographics of Egypt * Ancient Egypt, a civilization from c. 3200 BC to 343 BC ** Ancient Egyptians, ethnic people of ancient Egypt ** Ancient Egyptian architecture, the architectural structure style ** Ancient Egyptian cuisine, the cuisine of ancient Egypt ** Egyptian language, the oldest known language of Egypt and a branch of the Afroasiatic language family * Copts, the ethnic Egyptian Christian minority ** Coptic language or Coptic Egyptian, the latest stage of the Egyptian language, spoken in Egypt until the 17th c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arab Inventions
Arabs (, , ; , , ) are an ethnic group mainly inhabiting the Arab world in West Asia and North Africa. A significant Arab diaspora is present in various parts of the world. Arabs have been in the Fertile Crescent for thousands of years. In the 9th century BCE, the Assyrians made written references to Arabs as inhabitants of the Levant, Mesopotamia, and Arabia. Throughout the Ancient Near East, Arabs established influential civilizations starting from 3000 BCE onwards, such as Dilmun, Gerrha, and Magan, playing a vital role in trade between Mesopotamia, and the Mediterranean. Other prominent tribes include Midian, ʿĀd, and Thamud mentioned in the Bible and Quran. Later, in 900 BCE, the Qedarites enjoyed close relations with the nearby Canaanite and Aramaean states, and their territory extended from Lower Egypt to the Southern Levant. From 1200 BCE to 110 BCE, powerful kingdoms emerged such as Saba, Lihyan, Minaean, Qataban, Hadhramaut, Awsan, and Homerite em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Structures
A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping levels are present in the same crystal, they form a semiconductor junction. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others. Silicon is a critical element for fabricating most electronic circuits. Semiconductor devices can display a range of different useful properties, such as passing current more easily in one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectrics
In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarised, but also reorient so that their symmetry axes align to the field. The study of dielectric properties concerns storage and dissipation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QBD (electronics)
QBD is the term applied to the charge-to-breakdown measurement of a semiconductor device. It is a standard destructive test method used to determine the quality of gate oxides in MOS devices. It is equal to the total charge passing through the dielectric layer (i.e. electron or hole fluence multiplied by the elementary charge) just before failure. Thus QBD is a measure of time-dependent gate oxide breakdown. As a measure of oxide quality, QBD can also be a useful predictor of product reliability under specified electrical stress conditions. Test method Voltage is applied to the MOS structure to force a controlled current through the oxide, i.e. to inject a controlled amount of charge into the dielectric layer. By measuring the time after which the measured voltage drops towards zero (when electrical breakdown occurs) and integrating the injected current over time, the charge needed to break the gate oxide is determined. This gate charge integral is defined as: Q_\text = \i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B (programming language), B, C (programming language), C, C++, S (programming language), S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telepho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mohamed M
Muhammad (8 June 632 CE) was an Arab religious and political leader and the founder of Islam. According to Islam, he was a prophet who was divinely inspired to preach and confirm the monotheistic teachings of Adam, Noah, Abraham, Moses, Jesus, and other prophets. He is believed to be the Seal of the Prophets in Islam, and along with the Quran, his teachings and normative examples form the basis for Islamic religious belief. Muhammad was born in Mecca to the aristocratic Banu Hashim clan of the Quraysh. He was the son of Abdullah ibn Abd al-Muttalib and Amina bint Wahb. His father, Abdullah, the son of tribal leader Abd al-Muttalib ibn Hashim, died around the time Muhammad was born. His mother Amina died when he was six, leaving Muhammad an orphan. He was raised under the care of his grandfather, Abd al-Muttalib, and paternal uncle, Abu Talib. In later years, he would periodically seclude himself in a mountain cave named Hira for several nights of prayer. When he was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Passivation
A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is the portion with which other materials first interact. The surface of an object is more than "a mere geometric solid", but is "filled with, spread over by, or suffused with perceivable qualities such as color and warmth". The concept of surface has been abstracted and formalized in mathematics, specifically in geometry. Depending on the properties on which the emphasis is given, there are several inequivalent such formalizations that are all called ''surface'', sometimes with a qualifier such as algebraic surface, smooth surface or fractal surface. The concept of surface and its mathematical abstractions are both widely used in physics, engineering, computer graphics, and many other disciplines, primarily in representing the surfaces o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gate Oxide
The gate oxide is the dielectric layer that separates the metal gate, gate terminal of a MOSFET (metal–oxide–semiconductor field-effect transistor) from the underlying source and drain terminals as well as the conductive channel that connects source and drain when the transistor is turned on. Gate oxide is formed by thermal oxidation of the silicon of the channel to form a thin (5 - 200 nm) insulating layer of silicon dioxide. The insulating silicon dioxide layer is formed through a process of self-limiting oxidation, which is described by the Deal–Grove model. A conductive gate material is subsequently deposited over the gate oxide to form the transistor. The gate oxide serves as the dielectric layer so that the gate can sustain as high as 1 to 5 MV/cm transverse electric field in order to strongly modulate the electrical conductance, conductance of the channel. Above the gate oxide is a thin electrode layer made of a electrical conductor, conductor which can be aluminium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field-effect Transistor
The field-effect transistor (FET) is a type of transistor that uses an electric field to control the current through a semiconductor. It comes in two types: junction FET (JFET) and metal-oxide-semiconductor FET (MOSFET). FETs have three terminals: ''source'', ''gate'', and ''drain''. FETs control the current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use either electrons (n-channel) or holes (p-channel) as charge carriers in their operation, but not both. Many different types of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The most widely used field-effect transistor is the MOSFET (metal–oxide–semiconductor field-effect transistor). History The concept of a field-effect transistor (FET) was first patented by the Austr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
