US PATENT SUBCLASS 257 / 603
AVALANCHE DIODE (E.G., SO-CALLED "ZENER" DIODE HAVING BREAKDOWN VOLTAGE GREATER THAN 6 VOLTS)

Current as of: June, 1999
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257 /   HD   ACTIVE SOLID-STATE DEVICES (E.G., TRANSISTORS, SOLID-STATE DIODES)

603AVALANCHE DIODE (E.G., SO-CALLED "ZENER" DIODE HAVING BREAKDOWN VOLTAGE GREATER THAN 6 VOLTS) {2}
604  DF  .~> Microwave transit time device (e.g., IMPATT diode)
605  DF  .~> With means to limit area of breakdown (e.g., guard ring having higher breakdown voltage) {1}

DEFINITION

Classification: 257/603

AVALANCHE DIODE (E.G., SO-CALLED "ZENER" DIODE HAVING BREAKDOWN VOLTAGE GREATER THAN 6 VOLTS):

(under the class definition) Subject matter configured to operate in a manner in which an external voltage is applied in the reverse-conducting direction of the device junction with sufficient magnitude to cause the potential barrier at the junction to breakdown due to electrons or holes gaining sufficient speed to dislodge valence electrons and thus create more hole-electron current carriers by an avalanche process.

(1) Note. This includes the so-called "Zener" diode using silicon as a semiconductor which has a breakdown voltage greater than 6 volts. True Zener diodes conduct by reverse tunneling, and are classified in subclass 106. However, many avalanche breakdown diodes which are classifiable in subclass 603 are called "Zener" diodes even though the breakdown mechanism is avalanche multiplication, rather than tunneling. In silicon, pn junctions which break down at less than 5 volts, do so by reverse tunneling, while those that break down at above 6 volts, do so by avalanche multiplication.

(2) Note. See the illustration, below: [figure]

SEE OR SEARCH THIS CLASS, SUBCLASS:

106, for a reverse bias tunneling diode (Zener diode).

199, for an avalanche diode having a heterojunction.

481, for a Schottky barrier avalanche diode.

551, for an avalanche diode used as a voltage reference element combined with pn junction isolation means in an integrated circuit. SEE OR SEARCH CLASS

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,

185+, for stable state circuits which may include an avalanche diode; subclass 326 for limiting, clipping, or clamping utilizing an avalanche diode; subclass 502 for gating circuits utilizing an avalanche diode; and subclass 584 for miscellaneous circuits utilizing an avalanche diode.

438, Semiconductor Device Manufacturing: Process,

91, for methods of making a light responsive avalanche diode and subclass 380 for making an avalanche diode utilizing a semiconductor substrate.