US5489539A
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Method of making quantum well structure with self-aligned gate
Assignee: The AT&T MVPD Group LLC
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Filing: 1994-01-10
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Granted: 1996-02-06
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Expires: 2014-01-10
Abstract
Abstract Quantum well structures are fabricated by use of a process employing a Focused Ion Beam (FIB) scanning in the surface of a semiconductor substrate. The quantum well structures thus fabricated include Resonant Tunneling Transistors (RRTs) and one dimensional quantum wire devices, fabricated in conventional Metal Semiconductor Field Effect Transistors (MESFETs) or in High Electron Mobility Transistors (HEMTs). The RRT comprises a pair of implant barriers in the semiconductor substrate, whereby charge carriers are capable of tunneling through the implant barriers into the quantum well during the state of resonance. The one dimensional quantum wire device comprises a multiplicity of implant barriers disposed in the semiconductor substrate substantially parallel to the travelling direction of the charge carriers. The intersection of the implant barriers and the two dimensional gas (2DEG) inside the HEMT enclose truly one dimensional quantum wells which enable electrons to travel therethrough with high mobility. In addition, the potentials of the quantum wells or quantum wires are controlled by a self-aligned gate, such as a T-gate.
Inventors
- 👤 Randall L. Kubena
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:54
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/014; B; B82; B82Y; B82Y10/00; H10D30/202; H10D30/40; H10D30/43; H10D48/00; H10D48/01; H10D48/031; H10D48/032; H10D62/00; H10D62/80; H10D62/85; H10D62/852; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/949; Y10S438/962
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
108 words
A method of forming a quantum well structure, comprising the steps of: providing a semiconductor substrate; forming a masking layer on said semiconductor substrate; forming a gate opening with a T-gate profile through said masking layer; forming a plurality of potential barriers by scanning said gate opening with a focused ion beam substantially parallel to an axis between source and drain locations that are spaced from and on opposite sides of said gate opening, thereby defining a plurality of one dimensional quantum wells between the potential barriers; depositing a first conductive material into said gate opening to form a T-gate on said substrate; and removing said masking layer.
Claim 2
Independent Claim
108 words
A method of forming a quantum well structure, comprising the steps of: providing a semiconductor substrate; forming a masking layer on said semiconductor substrate; forming a gate opening with a T-gate profile through said masking layer; forming a plurality of potential barriers by scanning said gate opening with a focused ion beam substantially parallel to an axis between source and drain locations that are spaced from and on opposite sides of said gate opening, thereby defining a plurality of one dimensional quantum wells between the potential barriers; depositing a first conductive material into said gate opening to form a T-gate on said substrate; and removing said masking layer.
Claim 3
Dependent Claim
77 words
The method of forming a quantum well structure as set forth in claim 1, wherein said first conductive material is deposited into said gate opening to form a T-gate, and further comprising the step of depositing a second conductive material onto said substrate after the removal of said masking layer using said T-gate as a mask so that said second conductive material is deposited on said substrate at said source and drain locations lateral to said T-gate.
Claim 4
Dependent Claim
31 words
The method of forming a quantum well structure as set forth in claim 1, further comprising the step of annealing said quantum well structure after said masking layer has been removed.
Claim 5
Independent Claim
91 words
A method of forming a resonant tunneling structure, comprising the steps of: providing a semiconductor substrate; forming a masking layer on said semiconductor substrate; forming a gate opening through said masking layer; forming a plurality of potential barriers by scanning said gate opening with a focused ion beam substantially perpendicular to an axis between source and drain locations that are spaced from and on opposite sides of said gate opening; depositing a first conductive material into said gate opening to form a T-gate on said substrate; and removing said masking layer.
Claim 6
Independent Claim
91 words
A method of forming a resonant tunneling structure, comprising the steps of: providing a semiconductor substrate; forming a masking layer on said semiconductor substrate; forming a gate opening through said masking layer; forming a plurality of potential barriers by scanning said gate opening with a focused ion beam substantially perpendicular to an axis between source and drain locations that are spaced from and on opposite sides of said gate opening; depositing a first conductive material into said gate opening to form a T-gate on said substrate; and removing said masking layer.
Claim 7
Dependent Claim
24 words
The method of forming a resonant tunneling structure as set forth in claim 4, wherein said gate opening is formed with a T-gate profile.
Claim 8
Dependent Claim
78 words
The method of forming a resonant tunneling structure as set forth in claim 5, wherein said first conductive material is deposited into said gate opening to form a T-gate, and further comprising the step of depositing a second conductive material onto said semiconductor substrate after the removal of said masking layer using said T-gate as a mask so that said second conductive material is deposited on said substrate at said source and drain locations lateral to said T-Gate.
Claim 9
Dependent Claim
74 words
The method of forming a resonant tunneling structure as set forth in claim 4, further comprising the steps of: forming a second masking layer on said semiconductor substrate after the first masking layer has been removed; forming source and drain openings through said second masking layer at said source and drain locations, respectively; depositing a second conductive material into said source and drain openings onto said semiconductor substrate; and removing said second masking layer.
Claim 10
Dependent Claim
31 words
The method of forming a resonant tunneling structure as set forth in claim 4, further comprising the step of annealing said resonant tunneling structure after said masking layer has been removed.
Claim 11
Dependent Claim
30 words
The method of forming a resonant tunneling structure as set forth in claim 8, wherein said resonant tunneling structure is annealed at a temperature between 450 and 700 degrees Celsius.
Claim 12
Independent Claim
71 words
A method of forming a resonant tunneling structure, comprising the steps of: forming a material layer on the surface of a semiconductor substrate; forming a contact opening through said material layer; scanning said contact opening with a focused ion beam to form potential barriers in said semiconductor substrate; depositing a first conductive material into said contact opening to form a first contact on said semiconductor substrate; and removing said material layer.
Claim 13
Independent Claim
71 words
A method of forming a resonant tunneling structure, comprising the steps of: forming a material layer on the surface of a semiconductor substrate; forming a contact opening through said material layer; scanning said contact opening with a focused ion beam to form potential barriers in said semiconductor substrate; depositing a first conductive material into said contact opening to form a first contact on said semiconductor substrate; and removing said material layer.
Claim 14
Dependent Claim
33 words
The method of forming a resonant tunneling structure as set forth in claim 10, further comprising the step of annealing said resonant tunneling structure at a temperature between 450 and 700 degrees Celsius.
Claim 15
Dependent Claim
39 words
The method of forming a resonant tunneling structure as set forth in claim 10, wherein said contact opening is formed with a T-shaped profile, and said first conductive material is deposited into said contact opening to form a T-gate.
Claim 16
Dependent Claim
61 words
The method of forming a resonant tunneling structure as set forth in claim 12, further comprising the step of depositing a second conductive material onto said substrate after the removal of said material layer using the T-gate as a mask so that said second conductive material is deposited on said substrate at spaced locations on opposite sides of said contact opening.
Claim 17
Dependent Claim
73 words
The method of forming a resonant tunneling structure as set forth in claim 10, further comprising the steps of: forming a second material layer on said substrate after said first material layer has been removed; forming second and third openings through said second material layer on opposite sides of said contact opening; depositing said second and third contacts onto said substrate through said second and third openings; and removing said second material layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-05 | 1999-08-07 | 2000-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-05 | 2003-08-07 | 2004-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-05 | 2007-08-07 | 2008-02-06 | $7700.00 | Window Closed / Lapsed |