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US4618767A
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Low-energy scanning transmission electron microscope
Assignee: International Business Machines Corp
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Filing: 1985-03-22
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Granted: 1986-10-21
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Expires: 2005-03-22
Abstract
Abstract Low-energy scanning transmission electron microscopy is achieved by using a sharply pointed electrode as a source of electrons having energies less than 10 eV and scanning the electron emitting pointed source across the surface of a self-supported thin film of material to be investigated at an essentially constant distance on the order of nanometers. The electrons transmitted through the specimen are sensed by a suitable detector and the output signal of the detector is used to control a display unit, such as a CRT display or a plotter. A scanning signal generating means simultaneously controls both the scanning of the electron emitting point source and the display unit while a separation control unit holds the distance between the point source and surface at a constant value. The electron emitting point source and associated mechanical drives as well as the specimen film and electron detector are all positioned in a vacuum chamber and isolated from vibration by a damped suspension apparatus.
Inventors
- 👤 David A. Smith
- 👤 Oliver C. Wells
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:15
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/26; H01J37/28; H01J2237/00; H01J2237/02; H01J2237/024; H01J2237/0245; H01J2237/15; H01J2237/1502; H01J2237/1503; H01J2237/25; H01J2237/2505; H01J2237/2583; H01J2237/26; H01J2237/28; H01J2237/2802; Y; Y10; Y10S; Y10S977/00; Y10S977/84; Y10S977/849; Y10S977/852; Y10S977/86
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
76 words
A low-energy scanning transmission electron microscope, comprising: a pointed electrode; a thin film sample spaced less than 100 nanometers from said electrode; means providing flow of low-energy electrons from said electrode to said spaced sample without focusing elements, some of the low-energy electrons passing through the sample; means for mechanically scanning said pointed electrode with respect to the sample; and electron sensing means for detecting low-energy electrons from said electrode which have passed through the sample.
Claim 2
Dependent Claim
76 words
A low-energy scanning transmission electron microscope, comprising: a pointed electrode; a thin film sample spaced less than 100 nanometers from said electrode; means providing flow of low-energy electrons from said electrode to said spaced sample without focusing elements, some of the low-energy electrons passing through the sample; means for mechanically scanning said pointed electrode with respect to the sample; and electron sensing means for detecting low-energy electrons from said electrode which have passed through the sample.
Claim 3
Dependent Claim
32 words
A microscope as defined in claim 1 and further comprising display means synchronized with said scanning means for producing an image representation of the low-energy electrons detected by said electron sensing means.
Claim 4
Dependent Claim
33 words
A microscope as defined in claim 1 and further comprising display means synchronized with said scanning means for producing a line scan representation of the low-energy electrons detected by said electron sensing means.
Claim 5
Dependent Claim
14 words
A microscope as defined in claim 1 wherein said thin film sample is self-supported.
Claim 6
Dependent Claim
19 words
A microscope as defined in claim 1 wherein said low-energy electrons have an energy less than 10 electron volts.
Claim 7
Dependent Claim
28 words
A microscope as defined in claim 1 wherien said electrode and thin film sample are spaced from each other by a distance which is less than 10 nanometers.
Claim 8
Dependent Claim
26 words
A microscope as defined in claim 6 wherein said electrode and thin film sample are spaced from each other by a distance of approximately 1 nanometer.
Claim 9
Dependent Claim
30 words
A microscope as defined in claim 1 wherein said means providing flow of low-energy electrons comprises a constant voltage source electrically connected between said electrode and said thin film sample.
Claim 10
Dependent Claim
30 words
A microscope as defined in claim 1 wherein said means providing flow of low-energy electrons comprises a constant current source electrically connected between said electrode and said thin film sample.
Claim 11
Dependent Claim
28 words
A microscope as defined in claim 1 and further comprising means for controlling the separation between said electrode and thin film sample such that it remains substantially constant.
Claim 12
Dependent Claim
54 words
A microscope as defined in claim 11 wherein said means for controlling separation comprises: means for applying a constant voltage between said electrode and said sample; means for measuring the current which flows from said electrode to said sample; and means for controlling the separation so as to make the measured current substantially constant.
Claim 13
Dependent Claim
52 words
A microscope as defined in claim 11 wherein said means for controlling separation comprises: means for driving a constant current between said electrode and said sample; means for measuring the voltage between said electrode and said sample; and means for controlling the separation so as to make the measured voltage substantially constant.
Claim 14
Dependent Claim
16 words
A microscope as defined in claim 10 wherein said controlled separation is less than 10 nanometers.
Claim 15
Dependent Claim
15 words
A microscope as defined in claim 13 wherein said controlled separation is about 1 nanometer.
References Cited (Backward Citations)
US4343993A
Cited
US4550257A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-10-20 | 1990-04-21 | 1990-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-20 | 1994-04-21 | 1994-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-20 | 1998-04-21 | 1998-10-21 | $7700.00 | Window Closed / Lapsed |