18WuD2x

630 silicon carbide • silver-oxide cell
silicon carbide Formula, SiC. A compound of silicon
and carbon valued as a semiconductor, an
abrasive material, and a refractory substance.
The commercial product is made by heating carbon
and sand to a high temperature in an electric
resistance furnace. Also called CARBORUNDUM.
silicon cell A type of photovoltaic cell using specially
processed silicon as the light-sensitive material.
This cell has a comparatively high voltage
output.
silicon-controlled rectifier Abbreviation, SCR. A
four-layer semiconductor device commonly used
in power control applications (e.g., light dimmers
and motor-speed controls). The electrodes are
called the anode, the cathode, and the gate. The
control signal is applied to the gate.
silicon-controlled switch Abbreviation, SCS. A
four-terminal semiconductor switching device
similar to the SILICON-CONTROLLED RECTI-
FIER. It is used for light-duty switching.
silicon crystal detector 1. See SILICON JUNC-
TION DIODE. 2. See SILICON POINT-CONTACT
DIODE. 3. A point-contact diode in which a lump
of silicon is contacted by either a fine wire (cat
whisker) or a blunt-tipped steel screw under
pressure.
silicon detector See SILICON CRYSTAL DETEC-
TOR.
silicon-diffused transistor A silicon bipolar transistor
fabricated by diffusion techniques. It is
characterized by high power-dissipation tolerance.
silicon diode A semiconductor diode in which the
semiconductor material is specially processed silicon.
Also see SILICON JUNCTION DIODE and
SILICON POINT-CONTACT DIODE.
silicon dioxide Formula, SiO 2 . A compound of silicon
and oxygen. In the passivation of transistors
and integrated circuits, a thin layer of silicon
dioxide is grown on the surface of the wafer to
protect the otherwise exposed junctions.
silicone A polymeric material characterized by a
recurring chemical group containing oxygen and
silicon atoms in the main chain as links. Various
silicone compounds have numerous uses in electronics.
silicon junction diode A semiconductor diode using
a pn junction in a silicon wafer. Compare SIL-
ICON POINT-CONTACT DIODE.
silicon on sapphire Abbreviation, SOS. Pertaining
to integrated-circuit fabrication in which a silicon
epitaxial layer is grown on a sapphire substrate.
silicon oxide A compound containing both silicon
monoxide and silicon dioxide, and having dielectric
properties. It is used in the manufacture of
metal-oxide-semiconductor (MOS) devices.
silicon photocell A photocell using a silicon pn
junction as the light-sensitive medium.
silicon photodiode A silicon diode constructed so
that radiant energy can strike the barrier between
the P- and N-type materials. A reverse bias
is applied. When light falls on the P-N junction,
current flows. The current is proportional to the
intensity of the impinging energy, within certain
limits. The greatest sensitivity is in the near infrared
(IR). When energy of variable brightness
falls on the P-N junction under conditions of reverse
bias, the output current follows the intensity
variations. This makes the device useful in
fiberoptic communications systems.
silicon point contact The contact between a
pointed metal wire (cat whisker) and a silicon
wafer.
silicon point-contact diode A diode in which a
tungsten wire (cat whisker) contacts a wafer of
single-crystal silicon. It is useful at ultra high frequencies
(UHF). Compare SILICON JUNCTION
DIODE.
silicon rectifier A semiconductor rectifier consisting
essentially of a junction between n- and p-
type silicon inside a specially processed wafer or
plate of single-crystal silicon.
silicon resistor See CRYSTAL RESISTOR.
silicon solar cell A relatively heavy-duty photovoltaic
cell using specially processed silicon as
the light-sensitive material.
silicon steel A high-permeability, high-resistance
steel containing 2 to 3 percent silicon. It is used
as core material in transformers and other electromagnetic
devices.
silicon transistor A transistor in which the semiconductor
material is single-crystal silicon.
silk-enameled wire Wire whose insulation is a
layer of silk on top of an enamel coating.
silver Symbol, Ag. A precious metallic element.
Atomic number, 47. Atomic weight, 107.87. It is
used in circuits where low resistance and high Q
are mandatory.
silver arsenide trisulfide See PROUSTITE.
silver-dollar construction Printed-circuit assembly
on a disk-shaped board, about the size of a
U.S. silver dollar.
silver-mica capacitor A fixed capacitor made by
painting or depositing a silver layer (capacitor
plate) on both faces of a thin mica film (dielectric
separator).
silver migration The undesirable tendency of silver
to be removed from one location and deposited
in another under adverse environmental
conditions.
silver-oxide battery A set of two or more silveroxide
cells stacked one atop the other, electrically
connected in series. The resulting battery has a
cylindrical shape. A set of four cells provides approximately
6 volts under no-load conditions; a
battery of six cells provides 9 volts; a battery of
eight cells provides 12 volts. See also SILVER-
OXIDE CELL.
silver-oxide cell An electrochemical cell having a
button-like shape, small enough to fit inside a
wristwatch. There are several available sizes and
thicknesses, all with similar appearance. The