Spacistor
Encyclopedia
The spacistor was a type of transistor
developed in the 1950s as an improvement over the point-contact transistor
and the later alloy junction transistor. It offered much higher speed than earlier transistors.
It is composed of a P-N junction
with a wide depletion region
, inside which two additional contacts are made: the injector and the modulator. The P material was called the base and the N material was called the collector. The injector acted like a BJT (bipolar junction transistor
) emitter, the modulator like a base, and the collector like its BJT namesake. It achieved high speed by reducing the charge carrier
's transit time. It became obsolete in the early 1960s with the development of the diffusion transistor
.
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
developed in the 1950s as an improvement over the point-contact transistor
Point-contact transistor
A point-contact transistor was the first type of solid-state electronic transistor ever constructed. It was made by researchers John Bardeen and Walter Houser Brattain at Bell Laboratories in December 1947. They worked in a group led by physicist William Bradford Shockley...
and the later alloy junction transistor. It offered much higher speed than earlier transistors.
It is composed of a P-N junction
P-n junction
A p–n junction is formed at the boundary between a P-type and N-type semiconductor created in a single crystal of semiconductor by doping, for example by ion implantation, diffusion of dopants, or by epitaxy .If two separate pieces of material were used, this would...
with a wide depletion region
Depletion region
In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region or the space charge region, is an insulating region within a conductive, doped semiconductor material where the mobile charge carriers have diffused away, or have been forced away by an...
, inside which two additional contacts are made: the injector and the modulator. The P material was called the base and the N material was called the collector. The injector acted like a BJT (bipolar junction transistor
Bipolar junction transistor
|- align = "center"| || PNP|- align = "center"| || NPNA bipolar transistor is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons...
) emitter, the modulator like a base, and the collector like its BJT namesake. It achieved high speed by reducing the charge carrier
Charge carrier
In physics, a charge carrier is a free particle carrying an electric charge, especially the particles that carry electric currents in electrical conductors. Examples are electrons and ions...
's transit time. It became obsolete in the early 1960s with the development of the diffusion transistor
Diffusion transistor
A diffusion transistor is any transistor formed by diffusing dopants into a semiconductor substrate. Diffusion transistors include some types of both bipolar junction transistors and field-effect transistors...
.