US3626257A
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Semiconductor device with superlattice region
Assignee: International Business Machines Corp
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Filing: 1969-04-01
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Granted: 1971-12-07
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Expires: 1989-04-01
Abstract
Abstract The semiconductor device has two highly N-type end portions to which ohmic contacts are made, and a central portion which has a one dimensional spatial periodic variation, in its band-edge energy. This spatial periodic variation, or superlattice, is produced by doping or alloying to form a plurality of successive layers having alternating band-edge energies. The period of the spatial variation is less than the carrier mean free path, and is such as to form in momentum space a plurality of periodic minizones which are much smaller than the Brillouin zones. The device exhibits a bulk negative resistance and is used in oscillator and bistable circuits.
Inventors
- 👤 Leo Esaki
- 👤 Rudolf Ludeke
- 👤 Raphael Tsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:13
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H01; H01S; H01S5/00; H01S5/30; H01S5/32; H01S5/34; H03; H03B; H03B9/00; H03B9/12; H10; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8164; H10D62/8171; H10H; H10H20/00; H10H20/80; H10N; H10N80/00; H01S5/3425; Y; Y10; Y10S; Y10S148/00; Y10S148/065; Y10S148/067; Y10S148/072; Y10S148/097; Y10S148/169
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
21 words
The device of claim 1 wherein the width of each of said spatial periods is between 50 angstroms and 500 angstroms.
Claim 2
Dependent Claim
18 words
The semiconductor device of claim 1 wherein adjacent ones of said layers of semiconductor material are differently doped.
Claim 3
Dependent Claim
17 words
The semiconductor device of claim 1 wherein adjacent layers of said semiconductor material have different energy gaps.
Claim 4
Dependent Claim
19 words
The semiconductor device of claim 1 wherein said portion includes at least 20 of said layers of semiconductor material.
Claim 5
Dependent Claim
55 words
The semiconductor device of claim 1 wherein said superlattice structure includes a plurality of layers of equal thickness of the same semiconductor material, all of said layers being at least slightly N type, a first and alternaTe ones of said layers being less heavily N type than the second and alternate ones of said layers.
Claim 6
Dependent Claim
41 words
The semiconductor device of claim 1 wherein said superlattice portion includes a plurality of layers of equal thickness, and a first and alternate ones of said layers exhibit a smaller band gap than the second and alternate ones of said layers.
Claim 7
Dependent Claim
15 words
The device of claim 1 wherein each of said layers has essentially the same thickness.
Claim 8
Dependent Claim
17 words
The device of claim 8 wherein each of said layers is between 25 and 250 angstroms thick.
Claim 9
Dependent Claim
64 words
The device of claim 1 wherein said first and alternate layers having said first band-edge energy characteristic are formed of a first semiconductor material having a first band gap, and said second and alternate layers having said second band-edge energy characteristic are formed of an alloy including said first semiconductor material which alloy has a second band gap larger than said first band gap.
Claim 10
Dependent Claim
29 words
The device of claim 1 wherein said portion comprises a single semiconductor material and said layers are differently doped to provide said first and second different band-edge energy characteristics.
Claim 11
Dependent Claim
23 words
The device of claim 11 wherein said first and alternate layers are N type and said second and alternate layers are N+ type.
Claim 12
Dependent Claim
22 words
The device of claim 11 wherein said first and alternate layers are intrinsic and said second and alternate layers are N type.
Claim 13
Dependent Claim
53 words
The device of claim 1 wherein said means for applying a potential further includes first and second ohmic contacts to said body including said portion, and means connected to said contacts for applying an electric field to said portion, said portion of said body responsive to said field to exhibit a negative resistance.
Claim 14
Dependent Claim
30 words
The device of claim 14 further including a load connected to said body which provides a resistance such that said body is DC stable in first and second different states.
Claim 15
Dependent Claim
112 words
A semiconductor device which exhibits bulk negative resistance comprising: a superlattice structure formed from at least 10 layers of semiconductor material, the first and alternate layers thereof having a given band-edge energy, the second and alternate layers thereof having a band-edge energy different from said given band-edge energy and forming with said first and alternate layers at least five spatial periods, the width of each period being less than the mean free path of a carrier along the direction of the superlattice, and having an upper found of the order of 500 A., and means for applying a potential to said structure said potential being less than that needed for interband tunneling.
Claim 16
Dependent Claim
17 words
The device of claim 16 wherein each of said spatial periods is between 50 and 500 angstroms.
Claim 17
Dependent Claim
22 words
The device of claim 17 wherein said portion includes about 10 of said spatial periods and each period is about 100 angstroms.
Claim 18
Dependent Claim
22 words
A semiconductor device according to claim 16 further including means connected to said structure for deriving an electrical output from said structure.
Claim 19
Dependent Claim
143 words
An oscillator circuit comprising: a body of semiconductor material at least a portion of which is a superlattice structure having at least 10 layers of semiconductor material, the first and alternate layers thereof having a given band-edge energy, the second and alternate layers thereof having a band edge energy different from said given band-edge energy and forming with said first and alternate layers at least five spatial periods, the width of each period being less than the mean free path of a carrier along the direction of the superlattice and having an upper bound of the order of 500 A, and means connected serially with said structure for applying an electric field across said body in excess of a threshold field in response to which said body exhibits a negative resistance, and, a load coupled to said body for producing high frequency oscillations.
Claim 20
Dependent Claim
136 words
A bistablE circuit comprising: a body of semiconductor material at least a portion of which is a superlattice structure having at least 10 layers of semiconductor material, the first and alternate layers thereof having a given band-edge energy, the second and alternate layers thereof having a band-edge energy different from said given band-edge energy and forming with said first and alternate layers at least five spatial periods, the width of each period being less than the mean free path of a carrier along the direction of the superlattice, and having an upper bound of the order of 500A, and means connected serially with said superlattice structure for applying an electric field across said body, said body exhibiting a negative resistance when a field above a threshold field is applied, and, a load connected to said body.
Claim 21
Dependent Claim
110 words
A semiconductor device which exhibits bulk negative resistance comprising: a superlattice formed from at least 10 periodically alternating layers of semiconductor material, the first and alternate layers thereof having a given conductivity, the second and alternate layers thereof having a conductivity different from said given conductivity and forming with said first and alternate layers at least five spatial periods, the width of each period being less than the mean free path of carriers along the direction of the superlattice, and having an upper bound of the order of 500 A, and means for applying a voltage to said superlattice said voltage being less than that needed to produce interband tunneling.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |