Page 282 - An Introduction to Microelectromechanical Systems Engineering

Glossary

Accelerated life testing Also known as accelerated ageing, it is a methodology in
reliability that subjects a product to a high degree of operational and environmental
stresses, such as high temperature or voltage, in order to precipitate failure modes
that would normally manifest themselves in later stages of the product’s life.
Action potential A temporary change in the electrical voltage across the cellular
membrane of a nerve or muscle cell. Action potentials occur when the cell is stimu-
lated, especially by a nerve impulse. They form the mechanism by which sensory
and motor functions are transmitted across the neural system.
Amorphous silicon Silicon lacking a preferred crystalline orientation, typically
consisting of extremely fine grains each measuring a few nanometers in size.
Amplification In biochemistry, it is the process of making a large number of iden-
tical copies of a DNA fragment. In electronics, it is the process of increasing the
magnitude of an electrical voltage.

Anodic bonding A process to bond silicon to glass, specifically Pyrex™ 7740 or
equivalent.

Application-specific integrated circuit (ASIC) An electronic integrated circuit
with a functionality designed specifically for one particular application (e.g., the
detection of minute changes in capacitance and conversion into an output voltage).
Bandpass see filter.
Bandwidth The extent of the frequency response of a linear system. It is numeri-
cally defined as the difference between two corner frequencies where the system
gain is 3 dB below the maximal gain. An input signal with a frequency content
below or above the corner frequencies is severely attenuated by the system.

Bimetallic actuation The resulting motion when a stack of two materials having
dissimilar coefficients of thermal expansion is heated. One material expands more
than the other, giving rise to bending stresses. The amount of bending is propor-
tional to the temperature of the stack and the difference in coefficients of thermal
expansion.
BGA An acronym for ball grid array. A type of advanced ceramic package for
integrated circuits consisting of arrays of solder balls instead of electrical pins.
Bond pad A metal area on a die or wafer to which a gold or aluminum wire is
bonded. The wire and bond pad provide electrical connectivity between electrical
components on the die and electronic circuitry external to the die.

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