US5679962A — Semiconductor device and a single electron device

Claim 1

Independent Claim 206 words

A semiconductor device comprising: a semi-insulating semiconductor substrate having a top and a rear surface; a semiconductor layer structure comprising at least an undoped layer of a first semiconductor having a top surface and a rear surface, an undoped spacer layer comprising a second semiconductor having an electron affinity smaller than that of the first semiconductor and having a top surface and a rear surface, and an n type electron supply layer comprising the second semiconductor and having a top surface and a rear surface, successively grown on the top surface of the semi-insulating semiconductor substrate, the undoped layer having a flat top surface and a flat rear surface, the undoped spacer layer having, in cross-section at the top surface, a concavo-convex periodic structure, the rear surface being a flat surface disposed on the flat top surface of the undoped spacer layer, the n-type electron supply layer having, in cross-section at the top surface, a flat surface, the rear surface burying concavities of the concavo-convex structure of the undoped spacer layer; and a plurality of periodically spaced Schottky electrodes on the flat top surface of the n type electron supply layer, arranged in a direction perpendicular to the concavo-convex periodic structure of the undoped spacer layer.

Claim 2

Dependent Claim 206 words

A semiconductor device comprising: a semi-insulating semiconductor substrate having a top and a rear surface; a semiconductor layer structure comprising at least an undoped layer of a first semiconductor having a top surface and a rear surface, an undoped spacer layer comprising a second semiconductor having an electron affinity smaller than that of the first semiconductor and having a top surface and a rear surface, and an n type electron supply layer comprising the second semiconductor and having a top surface and a rear surface, successively grown on the top surface of the semi-insulating semiconductor substrate, the undoped layer having a flat top surface and a flat rear surface, the undoped spacer layer having, in cross-section at the top surface, a concavo-convex periodic structure, the rear surface being a flat surface disposed on the flat top surface of the undoped spacer layer, the n-type electron supply layer having, in cross-section at the top surface, a flat surface, the rear surface burying concavities of the concavo-convex structure of the undoped spacer layer; and a plurality of periodically spaced Schottky electrodes on the flat top surface of the n type electron supply layer, arranged in a direction perpendicular to the concavo-convex periodic structure of the undoped spacer layer.

Claim 3

Dependent Claim 23 words

The semiconductor device of claim 1 wherein said semiconductor substrate is GaAs, said first semiconductor is GaAs, and said second semiconductor is AlGaAs.

Claim 4

Dependent Claim 41 words

The semiconductor device of claim 1 wherein said semiconductor substrate is GaAs, and said semiconductor layer structure comprises at least an undoped InGaAs layer, an undoped AlGaAs spacer layer, and an n type AlGaAs electron supply layer that are successively grown.

Claim 5

Dependent Claim 45 words

The semiconductor device of claim 1 wherein said semiconductor substrate is GaAs, and said semiconductor layer structure comprises at least an undoped GaAs layer, an undoped InGaAs layer, an undoped AlGaAs spacer layer, and an n type AlGaAs electron supply layer that are successively grown.

Claim 6

Dependent Claim 23 words

The semiconductor device of claim 1 wherein said semiconductor substrate is InP, said first semiconductor is InGaAs, and said second semiconductor is AiInAs.

Claim 7

Dependent Claim 41 words

The semiconductor device of claim 1 wherein said semiconductor substrate is InP, and said semiconductor layer structure comprises at least an undoped InGaAs layer, an undoped AlInAs spacer layer, and an n type AlInAs electron supply layer that are successively grown.

Claim 8

Dependent Claim 45 words

The semiconductor device of claim 1 wherein said semiconductor substrate is InP, and said semiconductor layer structure comprises at least an undoped AiInAs layer, an undoped InGaAs layer, an undoped AlInAs spacer layer, and an n type AlInAs electron supply layer that are successively grown.

Claim 9

Dependent Claim 51 words

The semiconductor device of claim 1 wherein said semiconductor substrate is InP, and said semiconductor layer structure comprises at least an undoped AlInAs layer, an undoped InGaAs layer, an undoped AiInAs spacer layer, and an n type AlInAs electron supply layer, and an undoped AIInAs cap layer that are successively grown.

Claim 10

Dependent Claim 23 words

The semiconductor device of claim 1 wherein the cross-section of said concavo-convex periodic structure of said undoped spacer layer has a triangular configuration.

Claim 11

Dependent Claim 20 words

The semiconductor device of claim 1 wherein of said concavo-convex periodic structure of said undoped spacer layer has (111)B surfaces.

Claim 12

Dependent Claim 31 words

The semiconductor device of claim 1 wherein said concavo-convex periodic structure of said undoped spacer layer has a depth that periodically varies along a length direction of said concavo-convex periodic structure.

Claim 13

Dependent Claim 171 words

A single electron device comprising: a structure comprising at least an undoped layer of a first semiconductor, an undoped spacer layer comprising a second semiconductor having a smaller electron affinity than that of said first semiconductor, and an n type electron supply layer comprising said second semiconductor that are successively grown, portions of said undoped spacer layer having reverse triangular configurations in cross section and including at least at two points, said n-type electron supply layer burying regions of said undoped spacer layer that have reverse triangular configurations in cross section; a plurality of gate electrodes disposed on an upper surface of said semiconductor layer structure arranged in a direction perpendicular to the reverse triangular configurations of said undoped spacer layer; and at least one electron being stored in each of the electron storage regions in said undoped layer at each edge of said reverse triangular configuration, the at least one electron being switched by an application of a voltage to a respective gate electrode, thereby operating the single electron device.

Claim 14

Dependent Claim 171 words

A single electron device comprising: a structure comprising at least an undoped layer of a first semiconductor, an undoped spacer layer comprising a second semiconductor having a smaller electron affinity than that of said first semiconductor, and an n type electron supply layer comprising said second semiconductor that are successively grown, portions of said undoped spacer layer having reverse triangular configurations in cross section and including at least at two points, said n-type electron supply layer burying regions of said undoped spacer layer that have reverse triangular configurations in cross section; a plurality of gate electrodes disposed on an upper surface of said semiconductor layer structure arranged in a direction perpendicular to the reverse triangular configurations of said undoped spacer layer; and at least one electron being stored in each of the electron storage regions in said undoped layer at each edge of said reverse triangular configuration, the at least one electron being switched by an application of a voltage to a respective gate electrode, thereby operating the single electron device.

Claim 15

Dependent Claim 82 words

The single electron device of claim 12 wherein gate voltages that make an electron tunnel directly opposite said gate electrodes are applied to said gate electrodes and high frequency voltages having a phase shift of π therebetween are respectively applied to two of said gate electrodes, thereby enabling carrying of electrons sequentially, one by one, between a source electrode and a drain electrode in respective channels comprising the electron storage regions in said undoped layer opposite edges of said reverse triangular configuration.

Claim 16

Dependent Claim 85 words

The single electron device of claim 13 wherein said gate electrodes include a first pair and a second pair of gate electrodes so that respective pairs of said gate electrodes cover all of the plurality of channels comprising the electron storage regions in said undoped layer, providing an AND logic element in which only when voltages are applied to both of said first and second pairs of gate electrodes at the same time is a path between the source electrode and the drain electrode conductive.

Claim 17

Dependent Claim 86 words

The single electron device of claim 13 wherein said gate electrodes include a first pair and a second pair of gate electrodes so that respective pairs of said gate electrodes cover respective channels of the plurality of channels comprising the electron storage regions in said undoped layer, providing an OR logic element in which when a voltage is applied to at least one of said first and second pairs of gate electrodes, a path between a respective source electrode and a respective drain electrode is conductive.

Claim 18

Dependent Claim 73 words

The single electron device of claim 13 wherein said gate electrodes include a respective pair of gate electrodes disposed at respective channels of the plurality of channels comprising the electron storage regions in said undoped layer, providing a single electron device in which a transfer of a current value between the source electrode and the drain electrode having a current equal to an integer multiple of a single bit current flows as information.

Claim 19

Dependent Claim 76 words

The single electron device of claim 13 wherein said gate electrodes are disposed at respective channels comprising the electron storage regions in said undoped layer, including a plurality of drain electrodes disposed for independent operation for each of the respective channels, and said source electrode is a common electrode for said gate electrodes and said drain electrodes, providing a single electron device for information transfer employing each of the respective channels for one bit of information.

Claim 20

Dependent Claim 197 words

A single electron device comprising: a semi-insulating semiconductor substrate having a top and a rear surface; a semiconductor layer structure comprising at least an undoped layer of a first semiconductor having a top surface and a rear surface, an undoped spacer layer comprising a second semiconductor having an electron affinity smaller than that of said first semiconductor having a top surface and a rear surface, and an n type electron supply layer comprising said second semiconductor having a top surface and a rear surface, successively grown on the top surface of said semi-insulating substrate, portions of said undoped spacer layer having reverse triangular configurations in cross section having a depth that varies periodically along a length direction, thereby forming a plurality of shallow regions; an n-type electron supply layer of the second semiconductor burying the reverse triangular configurations of said undoped spacer layer; a plurality of gate electrodes disposed on an upper surface of said semiconductor layer structure, arranged in correspondence with the shallow regions in said undoped spacer layer; and a source electrode and a drain electrode disposed opposite each other with said gate electrodes between them on the upper surface of said semiconductor layer structure.

Claim 21

Dependent Claim 197 words

A single electron device comprising: a semi-insulating semiconductor substrate having a top and a rear surface; a semiconductor layer structure comprising at least an undoped layer of a first semiconductor having a top surface and a rear surface, an undoped spacer layer comprising a second semiconductor having an electron affinity smaller than that of said first semiconductor having a top surface and a rear surface, and an n type electron supply layer comprising said second semiconductor having a top surface and a rear surface, successively grown on the top surface of said semi-insulating substrate, portions of said undoped spacer layer having reverse triangular configurations in cross section having a depth that varies periodically along a length direction, thereby forming a plurality of shallow regions; an n-type electron supply layer of the second semiconductor burying the reverse triangular configurations of said undoped spacer layer; a plurality of gate electrodes disposed on an upper surface of said semiconductor layer structure, arranged in correspondence with the shallow regions in said undoped spacer layer; and a source electrode and a drain electrode disposed opposite each other with said gate electrodes between them on the upper surface of said semiconductor layer structure.

Claim 22

Dependent Claim 20 words

The single electron device of claim 12 wherein said reverse triangular configurations of said undoped spacer layer have (111)B surfaces.

Claim 23

Dependent Claim 37 words

The single electron device of claim 12 wherein said layer structure comprises at least an undoped InGaAs layer, an undoped AlGaAs spacer layer, and an n type AlGaAs electron supply layer and said semi-insulating substrate comprises GaAs.

Claim 24

Dependent Claim 41 words

The single electron device of claim 12 wherein said layer structure comprises at least an undoped GaAs layer, an undoped InGaAs layer, an undoped AlGaAs spacer layer, and an n type AlGaAs electron supply layer and said semi-insulating substrate comprises GaAs.

Claim 25

Dependent Claim 40 words

The single electron device of claim 12, wherein said structure comprises at least an undoped AlInAs layer, an undoped InGaAs layer, an undoped AlInAs spacer layer, and an n type AlInAs electron supply layer and said semi-insulating substrate comprises InP.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-10-20	2001-04-21	2001-10-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-10-20	2005-04-21	2005-10-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-10-20	2009-04-21	2009-10-21	$7700.00	Window Closed / Lapsed

Semiconductor device and a single electron device

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