|Born|| 12 June 1918|
|Died||17 February 2012 (aged 93)|
Kurt Lehovec (June 12, 1918 – February 17, 2012) was one of the pioneers of the integrated circuit. He innovated the concept of p-n junction isolation used in every circuit element with a guard ring: a reverse-biased p-n junction surrounding the planar periphery of that element. This patent was assigned to Sprague Electric.
An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material that is normally silicon. The integration of large numbers of tiny transistors into a small chip results in circuits that are orders of magnitude smaller, cheaper, and faster than those constructed of discrete electronic components. The IC's mass production capability, reliability and building-block approach to circuit design has ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones, and other digital home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs.
Because Lehovec was under salary with Sprague, he was paid only one dollar for this invention.
Lehovec was born June 12, 1918 in Ledvice, in northern Bohemia, of the Czech Republic. He was educated there and went to the US in 1947 under the auspices of Operation Paperclipwhich allowed scientists and engineers to emigrate. With Carl Accardo and Edward Jamgochian, he explained the first light-emitting diodes citing previous work by Oleg Losev.
Ledvice is a town in the Czech Republic located in the Teplice District in the Ústí nad Labem Region, about 7 km southwest of Teplice.
The Kingdom of Bohemia, sometimes in English literature referred to as the Czech Kingdom, was a medieval and early modern monarchy in Central Europe, the predecessor of the modern Czech Republic. It was an Imperial State in the Holy Roman Empire, and the Bohemian king was a prince-elector of the empire. The kings of Bohemia, besides Bohemia, also ruled the Lands of the Bohemian Crown, which at various times included Moravia, Silesia, Lusatia, and parts of Saxony, Brandenburg, and Bavaria.
The Czech Republic, also known by its short-form name, Czechia, is a landlocked country in Central Europe bordered by Germany to the west, Austria to the south, Slovakia to the east and Poland to the northeast. The Czech Republic covers an area of 78,866 square kilometres (30,450 sq mi) with a mostly temperate continental climate and oceanic climate. It is a unitary parliamentary republic, with 10.6 million inhabitants; its capital and largest city is Prague, with 1.3 million residents. Other major cities are Brno, Ostrava, Olomouc and Pilsen. The Czech Republic is a member of the European Union (EU), NATO, the OECD, the United Nations, the OSCE, and the Council of Europe.
The important case of fast ionic conduction in solid states is one in a surface space-charge layer of ionic crystals. Such conduction was first predicted by K. Lehovec in the paper “Space-charge layer and distribution of lattice defects at the surface of ionic crystals” ( J. Chem. Phys. 1953. V.21. P.1123 -1128). As a space-charge layer has nanometer thickness, the effect is directly related to nanoionics (nanoionics-I). The Lehovec effect forms a basis for a creation of multitude nanostructured fast ion conductors as used in modern portable lithium batteries and fuel cells.
Nanoionics is the study and application of phenomena, properties, effects and mechanisms of processes connected with fast ion transport (FIT) in all-solid-state nanoscale systems. The topics of interest include fundamental properties of oxide ceramics at nanometer length scales, and fast ion conductor /electronic conductor heterostructures. Potential applications are in electrochemical devices for conversion and storage of energy, charge and information. The term and conception of nanoionics were first introduced by A.L. Despotuli and V.I. Nikolaichik in January 1992.
In materials science, fast ion conductors are solids with highly mobile ions. These materials are important in the area of solid-state ionics, and are also known as solid electrolytes and superionic conductors. These materials are useful in batteries and various sensors. Fast ion conductors are used primarily in solid oxide fuel cells. As solid electrolytes they allow the movement of ions without the need for a liquid or soft membrane separating the electrodes. The phenomenon relies on the hopping of ions through an otherwise rigid crystal structure.
Lehovec was a Professor Emeritus at the University of Southern California in Los Angeles, California, and after retirement from USC Lehovec took to writing poetry.He lived in Southern California until his death in 2012 at the age of 93.
The University of Southern California is a private research university in Los Angeles, California. Founded in 1880, it is the oldest private research university in California. For the 2018–19 academic year, there were 20,000 students enrolled in four-year undergraduate programs. USC also has 27,500 graduate and professional students in a number of different programs, including business, law, engineering, social work, occupational therapy, pharmacy, and medicine. It is the largest private employer in the city of Los Angeles, and generates $8 billion in economic impact on Los Angeles and California.
Southern California is a geographic and cultural region that generally comprises California's southernmost counties, and is the second most populous urban agglomeration in the United States. The region is traditionally described as eight counties, based on demographics and economic ties: Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, and Ventura. The more extensive 10-county definition, which includes Kern and San Luis Obispo counties, is also used and is based on historical political divisions.
A diode is a two-terminal electronic component that conducts current primarily in one direction ; it has low resistance in one direction, and high resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other materials such as gallium arsenide and germanium are used.
A semiconductor material has an electrical conductivity value falling between that of a metal, like copper, gold, etc. and an insulator, such as glass. Their resistance decreases as their temperature increases, which is behaviour opposite to that of a metal. Their conducting properties may be altered in useful ways by the deliberate, controlled introduction of impurities ("doping") into the crystal structure. Where two differently-doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers which include electrons, ions and electron holes at these junctions is the basis of diodes, transistors and all modern electronics. Some examples of semiconductors are silicon, germanium, and gallium arsenide. After silicon, gallium arsenide is the second most common semiconductor used in laser diodes, solar cells, microwave frequency integrated circuits, and others. Silicon is a critical element for fabricating most electronic circuits.
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
A semiconductor device is an electronic component that exploits the electronic properties of semiconductor material, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced vacuum tubes in most applications. They use electrical conduction in the solid state rather that the gaseous state or thermionic emission in a vacuum.
The metal-oxide-semiconductor field-effect transistor is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, whose voltage determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. A metal-insulator-semiconductor field-effect transistor or MISFET is a term almost synonymous with MOSFET. Another synonym is IGFET for insulated-gate field-effect transistor.
Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic. It is a III-V direct bandgap semiconductor with a zinc blende crystal structure.
In physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. In a conducting medium, an electric field can exert force on these free particles, causing a net motion of the particles through the medium; this is what constitutes an electric current. In different conducting media, different particles serve to carry charge:
A High-electron-mobility transistor (HEMT), also known as heterostructure FET (HFET) or modulation-doped FET (MODFET), is a field-effect transistor incorporating a junction between two materials with different band gaps as the channel instead of a doped region. A commonly used material combination is GaAs with AlGaAs, though there is wide variation, dependent on the application of the device. Devices incorporating more indium generally show better high-frequency performance, while in recent years, gallium nitride HEMTs have attracted attention due to their high-power performance. Like other FETs, HEMTs are used in integrated circuits as digital on-off switches. FETs can also be used as amplifiers for large amounts of current using a small voltage as a control signal. Both of these uses are made possible by the FET’s unique current-voltage characteristics. HEMT transistors are able to operate at higher frequencies than ordinary transistors, up to millimeter wave frequencies, and are used in high-frequency products such as cell phones, satellite television receivers, voltage converters, and radar equipment. They are widely used in satellite receivers, in low power amplifiers and in the defense industry.
The planar process is a manufacturing process used in the semiconductor industry to build individual components of a transistor, and in turn, connect those transistors together. It is the primary process by which modern integrated circuits are built. The process was developed by Jean Hoerni, one of the "traitorous eight", while working at Fairchild Semiconductor, with a first patent issued 1959.
Jean Charles Athanase Peltier was a French physicist. He was originally a watch dealer, but at 30 years old took up experiments and observations in physics.
p–n junction isolation is a method used to electrically isolate electronic components, such as transistors, on an integrated circuit (IC) by surrounding the components with reverse biased p–n junctions.
An extrinsic semiconductor is one that has been doped; during manufacture of the semiconductor crystal a trace element or chemical called a doping agent has been incorporated chemically into the crystal, for the purpose of giving it different electrical properties than the pure semiconductor crystal, which is called an intrinsic semiconductor. In an extrinsic semiconductor it is these foreign dopant atoms in the crystal lattice that mainly provide the charge carriers which carry electric current through the crystal. The doping agents used are of two types, resulting in two types of extrinsic semiconductor. An electron donor dopant is an atom which, when incorporated in the crystal, releases a mobile conduction electron into the crystal lattice. An extrinsic semiconductor which has been doped with electron donor atoms is called an n-type semiconductor, because the majority of charge carriers in the crystal are negative electrons. An electron acceptor dopant is an atom which accepts an electron from the lattice, creating a vacancy where an electron should be called a hole which can move through the crystal like a positively charged particle. An extrinsic semiconductor which has been doped with electron acceptor atoms is called a p-type semiconductor, because the majority of charge carriers in the crystal are positive holes.
Oleg Vladimirovich Losev was a Russian scientist and inventor, who made significant discoveries in the field of semiconductor junctions.
In solid-state physics, a metal–semiconductor (M–S) junction is a type of electrical junction in which a metal comes in close contact with a semiconductor material. It is the oldest practical semiconductor device. M–S junctions can either be rectifying or non-rectifying. The rectifying metal–semiconductor junction forms a Schottky barrier, making a device known as a Schottky diode, while the non-rectifying junction is called an ohmic contact.
Nanofluidic circuitry is a nanotechnology aiming for control of fluids in nanometer scale. Due to the effect of an electrical double layer within the fluid channel, the behavior of nanofluid is observed to be significantly different compared with its microfluidic counterparts. Its typical characteristic dimensions fall within the range of 1–100 nm. At least one dimension of the structure is in nanoscopic scale. Phenomena of fluids in nano-scale structure are discovered to be of different properties in electrochemistry and fluid dynamics.
The idea of integrating electronic circuits into a single device was born when the German physicist and engineer Werner Jacobi developed and patented the first known integrated transistor amplifier in 1949 and the British radio engineer Geoffrey Dummer proposed to integrate a variety of standard electronic components in a monolithic semiconductor crystal in 1952. A year later, Harwick Johnson filed a patent for a prototype integrated circuit (IC).
The field-effect transistor (FET) is an electronic device which uses an electric field to control the flow of current. FETs are 3-terminalled devices, having a source, gate, and drain terminal. FETs control the flow of current by the application of a voltage to the gate terminal, which in turn alters the conductivity between the drain and source terminals.