Highly efficient subcritically doped electron-transfer effect devices

Claim 2

A device as defined in claim 2 wherein said cathode structure embodies means for providing an electron energy barrier of a selected height of less than about 0.33 electron-volts to control the injection of electron charge carriers into the active semiconductor body.

Claim 3

A device as defined in claim 3 wherein said cathode structure comprises an electron-blocking diffused metallic contact.

Claim 4

A device as defined in claim 3 wherein said cathode structure comprises an ion implantation-type electron-blocking contact.

Claim 5

A device as defined in claim 1 wherein said cathode structure embodies means for effecting a space charge limitation of the injected current flow to a desired level to thereby limit the injection of electron charge carriers into the active semiconductor body.

Claim 6

A device as defined in claim 6 wherein said cathode structure comprises a metallic contact that supplies a copious flow of electrons, and a region of intrinsic or lightly doped semiconductor having a selected thickness.

Claim 7

A device as defined in claim 6 wherein said cathode structure comprises a metallic contact that supplies a copious flow of electrons, and a region of compensated semiconductor having a selected thickness.

Claim 8

A device as defined in claim 1 wherein said cathode structure is responsive to external radiation to generate the desired number of injection charge carriers, and means for impinging the external radiation on said cathode structure.

Claim 9

A device as defined in claim 1 wherein said cathode structure embodies means for effecting current density compression of the injection current.

Claim 10

A device as defined in claim 10 wherein said cathode structure comprises a metallic contact that is nonblocking to electrons, and an electrically insulating layer having a matrix of holes interposed between the active semiconductor body and forming, through the holes, a plurality of electron-emitting cathode areas.

Claim 11

A solid state microwave amplifier circuit comprising a subcritically doped injection-current-limited electron-transfer effect device comprising at least an anode structure and a cathode structure and an active body of bulk semiconductor material therebetween having an noL product, where no is the equilibrium charge carrier density and L is the length of the active semiconductor body, below the critical value needed to sustain Gunn oscillation, characterized by a cathode structure that controls the injection of charge carriers to a desired value to maintain the electric field in the active semiconductor body in the immediate vicinity of the cathode structure and over the remainder of the length of the active semiconductor body at an approximately uniform selected value above the threshold electric field, said cathode structure further substantially maintaining the equilibrium charge density nO over most of the active semiconductor body, means for biasing said electron-transfer effect device with a unidirectional voltage that produces the selected above-threshold electric field, means for applying to said electron-transfer effect device an electric signal to be amplified, and output means for receiving the amplified signal.

Claim 12

A circuit as defined in claim 12 further including positive feedback means whereby said circuit functions as an oscillator circuit.

Claim 13

A circuit as defined in claim 12 including a plurality of said subcritically doped injection-current-limited electron-transfer effect devices connected in series circuit relationship to achieve higher power levels.

Claim 14

A solid-state negative resistance amplifier device comprising an anode structure, a cathode structure, and an active body of bulk semiconductor material therebetween that microscopically exhibits the electron-transfer effect when biased with a selected electric field above the characteristic threshold electric field and has an noL product, where no is the equilibrium charge carrier density and L is the length of the active semiconductor body, below the critical value needed to support Gunn oscillation, wherein said cathode structure controls the injection of charge carriers into the active semiconductor body to maintain the selected electric field in the active semiconductor body at an approximately uniform value above the threshold electric field in the immediate vicinity of said cathode structure and over the remainder of the length of the active semiconductor body.

Claim 15

A device as defined in claim 15 wherein said active bulk semiconductor material is selected from the group consisting of N-type gallium arsenide, cadmium telluride, indium phosphide, and zinc selenide.

Claim 16

A device as defined in claim 15 wherein said active bulk semiconductor material is gallium arsenide, and said cathode structure comprises a metallic contact that is partially blocking to electron charge carriers and provides an electronic energy barrier of less than about 0.33 electron-volts in the region of the metal-semiconductor interface.

Claim 17

A device as defined in claim 15 wherein said cathode structure comprises a metallic contact that is nonblocking to electron charge carriers and further comprises a region of the same semiconductor material as said active semiconductor body but of opposite conductivity-type, to thereby form a reverse biased PN junction that limits the injected charge carriers to the desired level.

Claim 18

A device as defined in claim 15 wherein said cathode structure comprises a metallic contact that is nonblocking to electron charge carriers, and further comprises a region of a foreign semiconductor or an insulator having a charge carrier energy barrier of a selected height.

Claim 19

A device as defined in claim 15 wherein said cathode structure comprises a metallic contact that is nonblocking to electron charge carriers, and further comprises a region of intrinsic or lightly doped or compensated semiconductor having a selected thickness to effect a desired space charge limitation of the injection current.

Claim 20

A device as defined in claim 15 wherein said cathode structure comprises a metallic contact that is nonblocking to electron charge carriers and makes electrical connection to only a selected portion of the cathode area of the active semiconductor body.

Claim 21

A solid state negative resistance amplifier device comprising an anode structure, a cathode structure, and an active body of bulk semiconductor material therebetween that microscopically exhibits the electron-transfer effect when biased with a selected electric field above the characteristic threshold electric field and has an n0L product, where no is the equilibrium charge carrier density and L is the length of the active semiconductor body, below the critical value needed to support Gunn osciLlation, wherein said anode and cathode structures both comprise metallic contacts that are nonblocking to electron charge carriers, and said active semiconductor body is tapered so as to have a small cross-sectional area adjacent said cathode structure and a large cross-sectional area adjacent said anode structure in order to control the injection of charge carriers into the active semiconductor body to maintain the selected electric field in the active semiconductor body at an approximately uniform value above the threshold electric field in the vicinity of said cathode structure and over the entire remainder of the length of the active semiconductor body.