Semiconductor Glossary

Semiconductor: A material that has a small band gap (the energy difference between the top of the valence band and the bottom of the conduction band) of around 0.7-6 eV. The material becomes conductive when it receives energy exceeding the band gap, but otherwise it is non-conductive.

SiC Wafer: A wafer made of SiC, a compound semiconductor material consisting of silicon (Si) and carbon (C). The material’s field strength for electrical breakdown is 10 times that of Si, and its band gap is three times wider. As SiC is also suitable for controlling a wide range of p- and n-type devices, it is attracting attention as a power device material that can be used in high-temperature, high-radiation environments. Because SiC has higher thermal conductivity than Si, it is also used to make semiconductor wafers.

Silicon Cycle: In the past when the consumption volume of semiconductors was dictated by supply and demand of computers, the semiconductor industry experienced periodic economic swings that repeated themselves roughly every four years—which is the rule of thumb known as the silicon cycle. The yearly growth of the semiconductor industry has in fact shown a cycle of peak and trough every three to four years until recently, but the pattern was broken as smartphones with short upgrade cycles became the sales driver in the increasingly diverse electronics market.

Silicon Interposer: Unlike a resin-based interposer, silicon interposer’s thermal expansion coefficient remains stable in a flip-chip mounting, which translates into beneficial electrical properties and excellent performance at high speeds and high frequencies, enabling more intricate wiring and bump formation.

Silicon Valley: A nickname for the southwestern portion of the San Francisco Bay Area in the U.S. where a large number of semiconductor chip manufacturers are concentrated. The name derives from the fact that monocrystalline silicon is the principal semiconductor material.

Silicon Wafer: A principal material for manufacturing semiconductors. Silicon wafers are made by melting silicon into a 99.999999999% pure cylindrical ingot and slicing it into discs of less than 1 mm in thickness. A grid of intricate circuit patterns is formed on the wafer surface, and then cut into separate semiconductor chips.

Single Electron Transistor: Unlike a conventional transistor that functions with an electrical current consisting of a flow of about 10,000 to 100,000 electrons, a single electron transistor uses a phenomenon called Coulomb blockade and can operate with a flow of only one electron. Once single electron transistors are successfully applied to ICs, they would significantly reduce the power consumption and heat generation levels associated with conventional ICs.

System In Package: A module that encloses a number of ICs and passive components (memory chips, ASICs, controllers, etc.) to function as an electronic system. SiP has an advantage over SoC (system on a chip) in terms of lead time and production cost.

Silicon On Insulator Wafer: A layered silicon-insulator-silicon wafer. Because it contains a layer of electrical insulator, the wafer is suitable for manufacturing high voltage-resistant devices. The transistor leakage can be curtailed by making the channel layer thinner, which could lower power consumption.

Spintronics: The study in engineering concerning the use of electric charge of an electron and its intrinsic spin. The word is a coinage combining “spin” and “electronics.” A representative achievement in this field of study is the discovery of the giant magnetoresistive effect in 1988, which came to be applied to magnetic heads of hard disc drives.

Sputtering: A process for depositing a thin film on the surface of a substrate. Also known as physical vapor deposition (PVD). The substrate to be covered by a film is placed in a vacuum together with the source material (target). When the target is hit by highly accelerated argon molecules, electrons, etc., the target molecules are ejected and deposited on the substrate, either directly or after chemically reacting with other gaseous materials introduced in the reactor.

Sputtering Equipment: A type of thin-film deposition tool. Its reactor is vacuumed and has no interference from the external environment. As a highly accelerated inactive material (such as argon) hits the target material like metals or ceramics, target molecules are ejected and deposited on the substrate, either directly or after chemically reacting with other gaseous materials introduced in the reactor.

Standard Cell: A type of semi-custom LSI that combines and interconnects pre-designed and standardized functional cells to enable a system on a chip. Each functional cell is optimally designed so the chip’s footprint is used more efficiently than in a gate array.

Stepper: A device for optically shrinking and transferring circuit patterns from a photomask (reticle) via lenses onto the wafer set on a stage. Light sources used for exposure include visible light (g-line), ultraviolet light (i-line), excimer laser (KrF, ArF, etc.) and so forth.

Structured ASIC: A type of ASIC introduced as an answer to continued chip scaling and shorter product cycles. A structured ASIC uses a number of fixed layers to reduce the cost of mask and mask development as well as to speed up development.

System LSI (also called System On A Chip): An LSI that integrates the functions and intellectual property (IP) cores of several separate ICs onto a single chip so it serves as a complete system. System LSIs, also known as systems on a chip (SoCs), are considered to be the future mainstream of semiconductor devices.