angstrom: A unit of length. 10,000 angstroms equals 1 micron. 10⁸ angstroms equals 1 cm. A silicon atom has a lattice spacing of 5.43 angstroms. Symbol: Å. See also micron.
channel: The region separating the source and drain of a field-effect transistor. The channel is designed to be normally "on" (conducting) for depletion-mode FETs, or normally "off" (insulating) for enhancement-mode FETs. With the application of a voltage to the gate electrode, the conducting properties of the channel are altered, thereby controlling the current across the channel. The length of the channel is an important parameter in determining the current of the FET, as well as its speed. See also source.
channeled array: A gate array base die with basic cells arranged in rows or columns. This arrangement permits routing in the spaces (channels) between rows of gates. Routing efficiency is usually high, near 90% or more. Routing is generally achieved by placing macros along single rows or columns. TGC103, TGC105 and TGC108 are examples of a channeled array.
channelless array: A gate array base die with basic cells covering the entire core with no row or column spacing. This array is often called a "sea-of-gates" (an LSI Logic, Inc. trademark) and is more difficult to route. Efficiencies are often 35% or less, due to complexity of the routing process. The advantage to this architecture is that macros can be placed in blocks, which increases macro performance. Larger TGC100 family members are channelless, and smaller members may be redesigned using this architecture.
chip: Also called a die. Popular term describing a section of a wafer that contains a discrete component or an integrated circuit. Many chips are made on a single wafer, then separated into dice and packaged individually.
clean room: A confined area in which the humidity, temperature, and particulate matter are precisely controlled within specified units. The "class" of the clean room defines the maximum number of particles of 0.3 micron size or larger that may exist in one cubic foot of space anywhere in the designated area. For example, in a Class 1 clean room only one particle of any kind may exist in one cubic foot of space. Newer clean rooms are typically Class 1-10, and are needed for manufacturing ICs with feature size close to 1 micron.
conductor: Any material, such as aluminum, copper or gold, that offers little resistance to the flow of electrical current.
contamination: The presence of unwanted particles, chemicals, or other substances.
current: The flow of electrons or holes. Usually measured in amperes (amp or A) or in fractions of an ampere (milli-amps or micro-amps). Current can be induced by application of an electric field through a conductor or by changing the electric field across a capacitor (displacement current.)
custom integrated circuit: An integrated circuit that requires a full set of masks specifically designed for a particular function or application. A custom IC is usually developed for a specific customer and may have to withstand harsh environments. Intersil offers a wide range of process technologies for analog, mixed signal and intelligent power applications. Intersil has more than 20 years experience in the custom market, specifically targeting applications requiring analog and radiation-hardening technologies.
defect: A chemical or structural irregularity that degrades the crystal structure of silicon or of the deposited materials that reside on its surface. Defects can be active mobile impurities that impact the electrical device characteristics over time, or inactive particulates that interfere with the photolithographic patterning. The most common defects in semiconductor processing are those originating from people (oil, cosmetics, sneezing, skin flakes, etc.)
deposition: The procedure in which materials are deposited onto a substrate. Usually refers to thin conducting or insulating films used to form MOS gates, capacitors, thin-film resistors, and the interconnect system for an IC.
die: A single square or rectangular piece of semiconductor material into which a specific electrical circuit has been fabricated. Plural: dice. Also called a chip.
diffusion: A high temperature process in which chemical impurities (dopants) enter and move through the crystalline lattice structure of a semiconductor material to change its electrical characteristics. The process takes place in a diffusion furnace, usually at temperatures between 850ºC and 1150ºC.
doping: The intentional introduction of a selected chemical impurity (dopant) into the crystal structure of a semiconductor to modify its electrical properties. For example, adding boron to silicon makes the material more P-type. Doping concentrations range from a few parts per billion (for resistive semiconductor regions) to a fraction of a percent (for highly conductive regions).
e-beam: Electron beam. Refers to a machine that produces a stream of electrons (electron beam) that can be used to expose photo-resists that are sensitive to such beams. Can be used to expose resists directly on a wafer or on a mask. Electron-beam lithography is a direct-write microprinting technique.
electron: An elementary atomic particle that carries the smallest negative electric charge (1.6x10^-19 coulombs). Electrons are light in mass, (1/1837 of the mass of the hydrogen atom), highly mobile, and orbit the nucleus of an atom.
etch: The process of removing material from a wafer (such as oxides or other thin films) by chemical, electrolytic or plasma (ion bombardment) means. Examples: nitride etch, oxide etch.
fab: Fabrication. In semiconductor manufacturing, fabrication usually refers to the front-end process of making devices and integrated circuits in semiconductor wafers, but does not include the package assembly (back-end) stages.
GaAs: Gallium Arsenide. A III-V compound semiconductor material used for making optoelectronic devices and high-frequency ICs. GaAs has a higher electron mobility than silicon, thus having the capability of producing higher-speed devices. Electrons in GaAs travel at twice the speed of those of silicon.
IC: Integrated Circuit. Plural: ICs (no apostrophe). See integrated circuit.
insulator: A material that is a poor conductor of electricity or heat, and used to separate conductors from one another or to protect personnel from active electrical devices. Examples: silicon dioxide (glass), silicon nitride, rubber, ceramics, wood.
integrated circuit (IC): An electronic circuit in which many active or passive elements are fabricated and connected together on a continuous substrate, as opposed to discrete devices, such as transistors, resistors, capacitors and diodes.
ion: An atom that has either gained or lost electrons, making it a charged particle (either positive or negative).
ion implantation: A means for adding dopants to semiconductor material. Charged atoms (ions) of elements such as boron, phosphorus or arsenic are accelerated by an electric field into the semiconductor material. Especially useful for very shallow (<1µm) distributions of dopants in a semiconductor. Ion implantation is usually done at room temperature, with the resulting implantation-induced lattice damage removed by annealing at temperatures of approximately 700ºC. More precise than diffusion doping.
junction: The interface plane within a semiconductor crystal, at which the number of P- and N-type carriers are exactly equal, with a surplus of P-type on one side of the junction and N-type on the other.
LED: Light-Emitting Diode. A semiconductor P-N junction diode that emits light under forward-bias conditions. The wavelength of the emitted light is a function of the semiconductor material. The crystal structure of silicon does not provide useful levels of light emission, but the structure of GaAs does, with an infrared emission wavelength.
lithography: The transfer of a pattern or image from one medium to another, as from a mask to a wafer. If light is used to effect the transfer, the term "photolithography" applies. "Microlithography" refers to the process as applied to images with features in the micrometer range. See also X-ray lithography.
micrometer: One-millionth (x10^-6 ) of a meter, or about 40 millionths of an inch. Synonymous with micron. Symbol: µm.
micron: Older term for micrometer. A metric unit of linear measure which equals one millionth of a meter. Symbol: µm
N-type semiconductor: A semiconductor type in which the density of holes in the valence band is exceeded by the density of electrons in the conduction band. N-type behavior is induced by the addition of donor impurities, such as arsenic or phosphorus, to the crystal structure of silicon. See also doping.
photolithography: Lithographic techniques involving light as the pattern transfer medium. See lithography.
photoresist: A light-sensitive liquid that is spread as a uniform thin film on a wafer or substrate. After baking to solidify the liquid, exposure of specific patterns is performed using a photomask. Material remaining after development shields regions of the wafer from subsequent etch or implant operations.
P-N junction: The basic structure formed by the intimate contact of P-type and N-type semiconductors. The important characteristic of a P-N junction is that it will conduct electric current with one polarity of applied voltage (forward bias) but will not conduct with the opposite polarity (reverse bias).
printed circuit: A circuit in which the wires or components have been replaced by a conductive pattern printed upon or bonded to the surface of an insulating board.
P-type semiconductor: A semiconductor type in which the density of electrons in the conduction band is exceeded by the density of holes in the valence band. P-type behavior is induced by the addition of acceptor impurities, such as boron, to the crystal structure of silicon. See also dopants .
quality control: A term denoting the functions or collection of duties that must be performed in order to carry out a company's quality objective. In some companies, quality control refers to a limited function, such as analysis of quality data or inspection of products before shipment to customers and discard or rework of flawed ones. At Implant Sciences Corporation, quality control (more often called Total Quality Management, or TQM) refers to a broad set of programs and responsibilities at all levels of the organization aimed at detecting and preventing errors at every step in the manufacturing process, from order entry through fabrication, packaging, shipment and invoicing the customer.
Quality First Initiative: An extensive and long-term initiative throughout Implant Sciences Corporation with three major objectives: (1) To increase customer satisfaction; (2) Grow the company by growing new products; and (3) Make continuous improvements in everything every business unit of the company does. The Quality First initiative is far more comprehensive in scope than application to products alone. Embedded in the initiative are such programs as Just In Time, Quality Involvement, Quality Audits, Employee Improvement Teams, and Total Quality Systems Reviews. The ultimate objective is a quantum and fundamental change in the way Implant Sciences Corporation does business, moving away from traditional, vertical management structures toward cross-functional teams. At the heart of the concept is customer satisfaction and the notion that end (external) customers are best satisfied as the result of a chain of satisfied internal customers.
semiconductor: A class of materials, such as silicon and germanium, whose electrical properties lie between those of conductors (such as copper and aluminum) and insulators (such as glass and rubber). A material that exhibits relatively high resistance in a pure state and much lower resistance when it contains small amounts of certain impurities. The term is also used to denote electronic devices made from semiconductor materials. See semiconductor device.
semiconductor device: An electronic device whose essential characteristics are governed by the flow of charge carriers within a semiconductor.
semicustom IC: An integrated circuit in which a portion of the circuit function is predefined and unalterable, while other portions can be configured to meet the designer's specific needs. Designers have the capability of designing application-specific circuits themselves, using either standard cell libraries or preconfigured arrays. Semicustom circuits can be analog, digital or mixed signal. Semicustom ICs are an area of Intersil's special strength--particularly analog and mixed signal semicustom circuits.
sensor: A component that provides an electrical signal in response to a specific physical or chemical stimulus such as heat, pressure, magnetic field, or a particular chemical vapor. Microsensors are the modern breed of sensor fabricated using processes similar to those for manufacturing ICs, or extensions of such processes. Integrated microsensors incorporate an integrated circuit on the same die as that used for the sensor element. Microsensors are expected to gain widespread acceptance in the 1990s for monitoring sophisticated automobile engine conditions.
silicon: A solid element that is abundantly available in the form of SiO₂ (glass). It is element 14 in the periodic table, with an atomic weight of 28.09. Silicon has a diamond crystal lattice, a density of 2.328 g/cm³ and a melting point of 1415ºC. Its extreme abundance, moderate processing temperatures, and the stability of its native oxide (SiO₂) have made it the electronic semiconductor material of choice for nearly four decades. It supports about $50 billion in IC and discrete sales annually.
silicon-on-insulator: See SOI.
SIM: See simulation, simulator.
SIMOX: Separation by IMplantation of OXygen. A process used to prepare SOI substrates. A very heavy dose of oxygen is implanted below the surface of a silicon wafer, after which the wafer is annealed at high temperature to convert the oxygen-implanted region into silicon dioxide. The growth of epitaxial silicon (on the surface, above the oxide layer) completes the SOI substrate. SIMOX is used in the Intersil RHD1 process to isolate individual components.
SIMS: Secondary Ion Mass Spectrometry.
SOS: Silicon-On-Sapphire. A CMOS technology in which a layer of silicon is epitaxially grown on a sapphire wafer, with specific regions subsequently etched away between individual transistors. Each device is thus totally isolated from other devices. Intersil is using SOS technology on 64K SRAMs in a process called TSOS-4 at Research Triangle Park, North Carolina. Since sapphire is an insulator, SOS is a subset of SOI (silicon-on-insulator) technology. Both SOI and SOS technologies provide for high levels of radiation hardness. Compare SOI.
source: One of the three regions that form a field-effect transistor. Majority-carriers (electrons in an N-channel FET or holes in a P-channel FET) originate at the source and flow across the channel to the drain as a result of the electric field applied between source and drain. See also channel .
total dose: Term used to describe the total exposure of an IC to ionizing radiation, typically gamma rays, energetic electrons, or X-rays. Most commercial ICs are very sensitive to ionizing radiation and degrade in their performance upon exposure. Intersil is the number-one supplier of rad-hard circuits, with total dose capabilities ranging from several kilorads to more than a megarad.
TQM: Total Quality Management. See Quality First initiative.
wafer: A thin slice, typically 10-30 mils thick, sawed from a cylindrical ingot (boule) of bulk semiconductor material (usually silicon), four to eight inches in diameter. Arrays of ICs or discrete devices are fabricated in the wafers during the manufacturing process. See IC, silicon.
X-ray lithography: The lithographic process for transferring patterns to a silicon wafer in which the electromagnetic radiation used is X-ray, rather than visible radiation. The shorter wavelength for X-rays (10-50 angstroms, versus 2000-3000 angstroms for ultra-violet radiation) minimizes diffraction, and extends the useful range of lithography towards 0.1µm. Optical lithography is currently thought to be limited to feature sizes above 0.25-0.3µm. See lithography and angstrom.
yield: The percent of wafers, dice, or packaged units conforming to specifications. The most common yields in the manufacturing process are: wafer fab yield (percentage of the wafers that complete wafer processing); wafer probe yield (the fraction of dice on a wafer that meet device specifications); assembly yield (percent of units that are assembled correctly); and final test yield (percent of packaged units that pass all device specifications).
Zener diode: A semiconductor P-N junction diode that has a controlled reverse-bias breakdown voltage, and is used to supply (clamp) a specific voltage for other protected components (for example in an IC). The Zener effect describes a tunnel breakdown phenomenon that is restricted to less than 5V. However, Zener diodes are traditionally used to describe any reverse-bias P-N junction device used to supply a specific voltage, even those of several hundred volts.