CN1126950C - Scan mode for scan tunnel microscope - Google Patents
Scan mode for scan tunnel microscope Download PDFInfo
- Publication number
- CN1126950C CN1126950C CN 01123918 CN01123918A CN1126950C CN 1126950 C CN1126950 C CN 1126950C CN 01123918 CN01123918 CN 01123918 CN 01123918 A CN01123918 A CN 01123918A CN 1126950 C CN1126950 C CN 1126950C
- Authority
- CN
- China
- Prior art keywords
- register
- voltage
- carry out
- program
- scanning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The present invention relates to a novel scanning mode which is suitable for a scanning tunnel microscope. Tunnel current is magnified into voltage of 0 to 5V by the amplifier of a measurement head, the voltage is converted into digital signals by a 16-bit A/D converter, and the digital signals are input in a computer. The computer carries out comparison operation conforming to a control program. Displacement regulation is continuously carried out when the digital signals do not conform to the control program. The computer sends out control signals when the digital signals conform to the control program. The control signals are converted into signals whose voltage is from 0V to 10V by a 20 bit D/A converter in an X direction (if the microscope scans to the position of a maximum point in the X direction, the converter is converted to be in a Y direction). The signals are sent to a high pressure generator in an X direction (when the microscope scans to the position of a maximum point in the X direction, the high pressure generator is converted to be in a Y direction). The high pressure generator amplifies voltage and power, and the voltage is amplified to be from 0V to 300V. The voltage is applied to piezoelectric ceramics, so the probe generates a preset displacement in an X direction (when the microscope scans to the position of a maximum point in the X direction, the displacement is converted to be in a Y direction) The processes are repeated, and scanning is completed until X and Y are both maximum values. The present invention improves developing speed, and also guarantees measurement accuracy.
Description
Technical field
The present invention relates to a kind of scanning tunnel microscope, particularly a kind of scan method that is applicable to scanning tunnel microscope.
Background technology
Scanning tunnel microscope can be divided into detection of permanent supreme people's court and constant flow method and detect according to the difference of detection mode.Permanent supreme people's court keeps needle point to do scanning motion on the surface level of a constant altitude above the sample, detects the variation of tunnel current, detects pattern and electrical characteristics that data set has been represented sample surfaces.Can make the pattern image of sample surfaces with this data set.Permanent supreme people's court is because height that needn't mobile needle point, and therefore, test speed is very fast; But it is only applicable to level and smooth relatively sample surfaces.Constant flow method is a height of adjusting needle point with the method for feedback, keeps constant tunnel current, and the movement locus of needle point height has reflected the variation of sample surfaces pattern.Constant flow method can be measured irregular surface accurately; But owing to need the ceaselessly height of mobile needle point, so test speed is slower.Because the unknown of sample surfaces pattern, so constant flow method is the main method of using in present this quasi-instrument.
The sweep limit of typical STM is from several nm-100um, and the data point of every row is 64 to 512 (some system reaches 1024), and scanning area is a square usually.Therefore, total number of data points is 64 * 64 to 512 * 512 (or 1024 * 1024), i.e. 4096-262,144 (1,048,576) point.
Common scan pattern is based on the pattern of time, preestablishes two kinds of sweep velocitys in instrument, slow scanning (being generally 2Hz) and scanning (being generally 10Hz) fast.Because protruding, the recessed variation of sample surfaces makes the image of gathering produce distortion, reduce distortion, will scan with slower speed.Because surface topography is unknown, STM have to constantly change the unevenness of sweep velocity with the accommodate sample surface topography, and early stage STM is to use a kind of velocity sweeping.For the accuracy of measuring, need to use lower velocity sweeping whole process; A kind of improved plan had been arranged afterwards, was exactly only to use at a slow speed at turning point, overcame the detection error of bringing when turning to; Recently, Park instrument company (second largest in the world STM manufacturing firm) announces, they have developed a kind of improved being called the scheme of " adapting to scanning ", it is when detection system detects the sudden change of pattern, automatically sweep speed is reduced to 2Hz, sweep speed is brought up to 10Hz in the part of relatively flat.It is said that this technology has been kept needle point and sample surfaces suitable measuring accuracy when brink interacts; Sweep velocity also improves a lot.
Existing scan pattern has two shortcomings, and the one, when scanner is swept to certain point,, after still will waiting for a regular time, descends by scanner the scanning of any again even tunnel current equals current setting value, and this is to make the reason that increases sweep time; The 2nd, when scanner was swept to certain point, if tunnel current is not equal to current setting value, scanner no matter whether the tunnel current value equals current setting value, just descend the scanning of a bit, made that the data of this point are a false data after waiting for a set time.
Summary of the invention
The objective of the invention is to overcome the deficiency of existing scan pattern, a kind of scan method that is applicable to scanning tunnel microscope is provided.
The object of the present invention is achieved like this: the scan method that is applicable to scanning tunnel microscope, the scanning motion that it is characterized in that X, Y scanner is the signal controlling that meets that is subjected to tunnel current detection and the generation of current setting value comparator circuit, its process is: the amplifier of tunnel current process gauge head is enlarged into the voltage of 0～5V, converts digital signal to through one 16 A/D converters and enters computing machine; Computing machine compares computing according to meeting control program, if do not meet, then proceeds displacement and regulates; If meet, then send control signal by computing machine, through directions X, if (directions X scans the maximum point position, then for the Y direction) 20 D/A converter convert the voltage signal of 0～10V to, send into directions X (if directions X scans the maximum point position, then be the Y direction) high pressure generator, carry out voltage and power amplification by high pressure generator, be enlarged into the voltage of 0～300V, be added on the piezoelectric ceramics, make probe produce a predetermined displacement of directions X (, then being the Y direction) if directions X scans the maximum point position.Repeat this process, until X, finish when Y is maximal value.
The scan method that is applicable to scanning tunnel microscope of the present invention had both improved video picture speed, had guaranteed measuring accuracy again.
Description of drawings
Fig. 1 is the process flow diagram that meets scan method.
Specific embodiments
Be applicable to the scan method of scanning tunnel microscope, the scanning motion of its X, Y scanner is the signal controlling that meets that is subjected to tunnel current detection and the generation of current setting value comparator circuit, its process is: the amplifier of tunnel current process gauge head is enlarged into the voltage of 0～5V, converts digital signal to through one 16 A/D converters and enters computing machine; Computing machine compares computing according to meeting control program, if do not meet, then proceeds displacement and regulates; If meet, then send control signal by computing machine, through directions X, if (directions X scans the maximum point position, then for the Y direction) 20 D/A converter convert the voltage signal of 0～10V to, send into directions X (if directions X scans the maximum point position, then be the Y direction) high pressure generator, carry out voltage and power amplification by high pressure generator, be enlarged into voltage (some piezoelectric ceramic devices of 0～300V, the amplification voltage of high pressure generator is 0～150V), be added on the piezoelectric ceramics, make probe produce a predetermined displacement of directions X (, then being the Y direction) if directions X scans the maximum point position, repeat this process, until X, when being maximal value, finishes Y.
As shown in Figure 1, the adjusting program of computing machine is: since 100, program is called in internal memory from hard disk, the CPU program that brings into operation; The 101st, CPU receives operator regional setting value M, maximum displacement Lm, maximum time sheet Tm by a keyboard entry, and scanning area is generally square, and M is the length of side; And regional setting value M, maximum displacement Lm and maximum time sheet Tm are deposited in respectively in regional setting value register, maximum displacement register and the maximum time sheet register, and the intermediate variable register of setting displacement simultaneously is L, and makes it equal Lm; The intermediate variable register of timeslice is T, and makes it equal Tm.
102 and 103 is that the register of setting Y direction and directions X is respectively Y and X, and makes Y and X all equal zero.
The 104th, to the judgement that meets, earlier the tunnel current value of the tunnel current value set and actual measurement is input to the input end of subtracter before judging respectively, the tunnel current value of setting is as minuend, the tunnel current value of actual measurement is as subtrahend, its output is the input end 1 that difference is connected on the difference comparer, is connected on input end 2 and 3 by the difference range of COMPUTER CALCULATION gained, if comparer output noble potential, then meet and be True, program changes 108 over to; If comparer output electronegative potential then meets and is False, program changes 105 over to.
105 carry out the L register subtracts 1 operation, and whether its difference is still composed the register to L, differentiate the L register simultaneously and equal zero; If be True, program changes 108 over to; If be False, program changes 106 over to.
106 carry out the T register subtracts 1 operation, and whether its difference is composed the register to T, differentiate the T register simultaneously and equal zero; If be True, program changes 108 over to; If be False, program changes 107 over to.
107 carry out feedback control module, and the Z axle is realized control, and after control program was finished, program flow returns to 104 continued to carry out.
108 values with intermediate variable register T, L revert to Tm, Lm.
109 carry out register X adds 1 operation, forwards 110 then to; If whether 110 numerical value of judging the X register be True, then forward 111 greater than regional setting value register M; If be False, then forward 104 to, continue to carry out.
111 carry out register Y adds 1 operation, forwards 112 then to; If whether 112 numerical value of judging y register be True, then forward 113 greater than regional setting value register M; If be False, then forward 103 to, continue to carry out.
113 finish this scanning process, and describe image according to output valve on graphoscope.
Claims (2)
1. scan method that is applicable to scanning tunnel microscope, the scanning motion that it is characterized in that X, Y scanner is the signal controlling that meets that is subjected to tunnel current detection and the generation of current setting value comparator circuit, its process is: the amplifier of tunnel current process gauge head is enlarged into the voltage of 0～5V, converts digital signal to through one 16 A/D converters and enters computing machine; Computing machine compares computing according to meeting control program, if do not meet, then proceeds displacement and regulates; If meet, then send control signal by computing machine, convert the voltage signal of 0～10V to through 20 D/A converter of directions X and Y direction, send into the high pressure generator of directions X and Y direction, carry out voltage and power amplification, be enlarged into the voltage of 0～300V by high pressure generator, be added on the piezoelectric ceramics, make probe produce a directions X and a predetermined displacement of Y direction, repeat this process, until X, finish when Y is maximal value.
2. the scan method that is applicable to scanning tunnel microscope according to claim 1 is characterized in that the adjusting program step of computing machine is:
First step: program is called in internal memory from hard disk, the CPU program that brings into operation;
Second step: CPU receives operator regional setting value M, maximum displacement Lm, maximum time sheet Tm by a keyboard entry, and scanning area is generally square, and M is the length of side; And regional setting value M, maximum displacement Lm and maximum time sheet Tm are deposited in respectively in regional setting value register, maximum displacement register and the maximum time sheet register, and the intermediate variable register of setting displacement simultaneously is L, and makes it equal Lm; The intermediate variable register of timeslice is T, and makes it equal Tm;
Third step: the register of setting Y direction and directions X is respectively Y and X, and makes Y and X all equal zero;
The 4th step: to the judgement that meets, earlier the tunnel current value of the tunnel current value set and actual measurement is input to the input end of subtracter before judging respectively, the tunnel current value of setting is as minuend, the tunnel current value of actual measurement is as subtrahend, its output is the input end 1 that difference is connected on the difference comparer, is connected on input end 2 and 3 by the difference range of COMPUTER CALCULATION gained, if comparer output noble potential, then meet and be True, program changes the 8th step over to; If comparer output electronegative potential then meets and is False, program changes the 5th step over to;
The 5th step: carry out the L register and subtract 1 operation, whether its difference is still composed the register to L, differentiate the L register simultaneously and equal zero; If be True, program changes the 8th step over to; If be False, program changes the 6th step over to;
The 6th step: carry out the T register and subtract 1 operation, whether its difference is composed the register to T, differentiate the T register simultaneously and equal zero; If be True, program changes the 8th step over to; If be False, program changes the 7th step over to;
The 7th step: carry out feedback control module, the Z axle is realized control, after control program was finished, program flow returns to the four steps continued to carry out the 8th step;
The 8th step: the value of intermediate variable register T, L is reverted to Tm, Lm;
The 9th step: carry out register X and add 1 operation, forward the tenth step then to;
The tenth step: if whether the numerical value of judging the X register be True, then forwards ten one step greater than regional setting value register M; If be False, then forward the 4th step to, continue to carry out;
The 11 step: carry out register Y and add 1 operation, forward the 12 step then to;
The 12 step: if whether the numerical value of judging y register be True, then forwards ten three step greater than regional setting value register M; If be False, then forward third step to, continue to carry out;
The 13 step: finish this scanning process, and on graphoscope, describe image according to output valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01123918 CN1126950C (en) | 2001-08-03 | 2001-08-03 | Scan mode for scan tunnel microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01123918 CN1126950C (en) | 2001-08-03 | 2001-08-03 | Scan mode for scan tunnel microscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1328254A CN1328254A (en) | 2001-12-26 |
| CN1126950C true CN1126950C (en) | 2003-11-05 |
Family
ID=4665364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01123918 Expired - Fee Related CN1126950C (en) | 2001-08-03 | 2001-08-03 | Scan mode for scan tunnel microscope |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1126950C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1303414C (en) * | 2004-12-28 | 2007-03-07 | 中山大学 | Dielectric loss microscope with scanning probe and measuring method therefor |
-
2001
- 2001-08-03 CN CN 01123918 patent/CN1126950C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1328254A (en) | 2001-12-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100578234C (en) | System and method for testing jiggle contact resistance | |
| CN1137648A (en) | Photoelectric digit rocking bar | |
| US6708132B1 (en) | Microsystems integrated testing and characterization system and method | |
| CN1699947A (en) | Calibration method and apparatus for silicon piezoresistive transducer in-circuit programmable automatic temperature compensation | |
| CN105491492A (en) | Self-calibration silicon microphone device and self-calibration method | |
| CN1699946A (en) | In-circuit programmable automatic temperature compensation silicon piezoresistive transducer | |
| US6341259B1 (en) | Microsystems integrated testing and characterization system and method | |
| CN1126950C (en) | Scan mode for scan tunnel microscope | |
| CN1187570C (en) | Method and device of fault detection and signal processing for differential transformer | |
| US5260572A (en) | Scanning probe microscope including height plus deflection method and apparatus to achieve both high resolution and high speed scanning | |
| CN108732385A (en) | Scan the drift correction device and auto-correction method of probe micro imaging system | |
| CN110082568B (en) | Scanning electrochemical microscope and correction method thereof | |
| CN1945468A (en) | Self searching optimum control of scanning type PI parameter | |
| CN108732387A (en) | A kind of probe sample distance controlling method and system of SICM | |
| US7312409B2 (en) | Touch pad and position detecting circuit and method thereof | |
| CN107703332A (en) | A kind of bearing calibration of piezoelectric scanner scanning range and system based on sweep speed | |
| CN1904583A (en) | Tunnel current measuring device of scanning tunnel microscope based on mutual incidence amplifier | |
| CN113267170A (en) | Three-main-truss steel beam transverse height difference adjusting method based on 3D laser scanning and model calculation data comparison feedback | |
| Wang et al. | A rate adaptive control method for improving the imaging speed of atomic force microscopy | |
| JP4695106B2 (en) | Method for determining height of chuck top and program recording medium recording this method | |
| Kuiper et al. | Improving the imaging speed of afm with modern control techniques | |
| WO2023195637A1 (en) | Potential gradient microscopy and driving method therefor | |
| CN114659465B (en) | Method and device for rapidly measuring micro-nano cross-scale surface structure | |
| CN115420808B (en) | Ultrasonic scanning automatic focusing method based on electronic door | |
| RU112504U1 (en) | SCAN TUNNEL MICROSCOPE |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |