US PATENT SUBCLASS 257 / 9
THIN ACTIVE PHYSICAL LAYER WHICH IS (1) AN ACTIVE POTENTIAL WELL LAYER THIN ENOUGH TO ESTABLISH DISCRETE QUANTUM ENERGY LEVELS OR (2) AN ACTIVE BARRIER LAYER THIN ENOUGH TO PERMIT QUANTUM MECHANICAL TUNNELING OR (3) AN ACTIVE LAYER THIN ENOUGH TO PERMIT CARRIER TRANSMISSION WITH SUBSTANTIALLY NO SCATTERING (E.G., SUPERLATTICE, QUANTUM WELL, OR BALLISTIC TRANSPORT DEVICE)

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

9THIN ACTIVE PHYSICAL LAYER WHICH IS (1) AN ACTIVE POTENTIAL WELL LAYER THIN ENOUGH TO ESTABLISH DISCRETE QUANTUM ENERGY LEVELS OR (2) AN ACTIVE BARRIER LAYER THIN ENOUGH TO PERMIT QUANTUM MECHANICAL TUNNELING OR (3) AN ACTIVE LAYER THIN ENOUGH TO PERMIT CARRIER TRANSMISSION WITH SUBSTANTIALLY NO SCATTERING (E.G., SUPERLATTICE, QUANTUM WELL, OR BALLISTIC TRANSPORT DEVICE) {5}
10  DF  .~> Low workfunction layer for electron emission, e.g., photocathode electron emissive layer {1}
12  DF  .~> Heterojunction {3}
28  DF  .~> Non-heterojunction superlattice (e.g., doping superlattice or alternating metal and insulator layers)
29  DF  .~> Ballistic transport device (e.g., hot electron transistor)
30  DF  .~> Tunneling through region of reduced conductivity {3}

DEFINITION

Classification: 257/9

THIN ACTIVE PHYSICAL LAYER WHICH IS (1) AN ACTIVE POTENTIAL WELL LAYER THIN ENOUGH TO ESTABLISH DISCRETE QUANTUM ENERGY LEVELS OR (2) AN ACTIVE BARRIER LAYER THIN ENOUGH TO PERMIT QUANTUM MECHANICAL TUNNELING OR (3) AN ACTIVE LAYER THIN ENOUGH TO PERMIT CARRIER TRANSMISSION WITH SUBSTANTIALLY NO SCATTERING (E.G., SUPERLATTICE QUANTUM WELL, OR BALLISTIC TRANSPORT DEVICE):

(under the class definition) Subject matter wherein the active material is a thin physical layer of material located between materials which have different electrical properties than the thin layer and wherein the thin active physical layer is (1) a potential well layer thin enough to establish discrete quantum energy levels or (2) a potential barrier layer thin enough to permit quantum mechanical tunneling or (3) a layer thin enough to permit carrier transmission therethrough with substantially no scattering of the carriers.

(1) Note. Examples of such devices are superlattice, quantum well, and ballistic transport devices.

(2) Note. Esaki tunneling is not the type of tunneling which this subclass and those indented thereunder contemplate. Esaki tunneling, while being quantum mechanical in nature, merely involves a tunneling barrier formed by a macroscopic depletion layer between n-type and p-type regions, but which neither a resonant tunneling barrier using controlled quantum mechanical charge confinement, a layer located between junctions, a thin layer as defined above. Esaki tunneling devices are found classified below, in subclasses 104+.

(3) Note. Active junction devices may employ a plurality of barrier junctions forming layers of material therebetween, but those layers are only classified in this subclass if they are thin enough to have the properties set forth in the definition. If those layers do not meet the definition, then the devices are classified below.

SEE OR SEARCH CLASS

372, Coherent Light Generators,

43+, for semiconductor lasers which may contain thin layer devices of this type for producing coherent light.