JPH02210633A - Scanning type tunnel current arithmetic processor - Google Patents

Abstract

PURPOSE:To speed up analog arithmetic processing by combining a mass-storage device consisting of a scanning type tunnel microscope with an input/output arithmetic means. CONSTITUTION:When information is read out, a driving circuit 14 applies opposite-phase voltages to electrode patterns 113a-113c and 212a and 212b arranged on 1st and 2nd cantilevers 11 and 21 alternately to vibrate the 1st lever 11 in a Y direction and the 2nd lever 21 in an X direction. At this time, the circuit 14 determines respective periods and attains synchronization, thereby scanning recording media 211 on the free end areas 210 of the opposite lever 21 with tunnel current end styli 1111-111n in the free end area 110 of the lever 11. Further, the circuit 14 performs servocontrol over a tunnel current from the center probe of a probe group 111 and applies this voltage to the electrode pattern 113b of the lever 11 to move the lever 11 vertically, thereby holding the distance between the probe group 111 and medium 211 constant. In this state, a mode selecting circuit is put in operation to read information out of the units 2111-211n of the medium 211.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to a storage device comprising a scanning tunneling current probe formed on a substrate using an IC process, and a recording body. For writing information on a recording medium,
The present invention also relates to a scanning tunnel current arithmetic processing device equipped with a signal processing circuit adapted to the scanning recording medium for reading information from the recording medium.

(Prior art) As is well known, when a DC voltage is applied between a sample and a tunneling current probe and the tip of the probe is brought close to a distance of several nm from the sample surface, the tunneling phenomenon causes the sample surface to Electrons move between the probe and the probe. This tunneling current value largely depends on the distance between the probe and the sample.

Therefore, we made the tip of the probe as sharp as 1 μm, treated the part where it approaches the atomic structure of the sample as if one atom of the probe was protruding, and added a servo circuit to the tunnel current detection circuit between the two. A scanning tunneling microscope (STM) has been realized in which a piezoelectric actuator is driven to control the distance between the two. The vertical movement of the probe in this type of STM corresponds to the atomic structure profile of the sample. Therefore, by scanning the probe two-dimensionally along the sample surface, the atomic structure can be output as a three-dimensional space together with the change in tunnel current.

It is also known that the relationship between the tunneling current flowing between the probe and the sample depends on the work functions of the materials that make up both. Therefore, the current obtained from the tip while it is being scanned is changed by either the unevenness information carved into the sample, the type of atoms in the sample material, or the charges trapped on the sample surface. .

FIG. 9 schematically shows a known scanning tunneling microscope. In FIG. 9, a DC voltage VB is applied to the probe T(ip) and the surface of the sample M, and the input terminal corresponding to the change in tunneling current 1b detected during scanning of the probe T(ip) is It is supplied to the preamplifier PA adjusted by the reference voltage Vref. Then, the control voltage Ve output from the preamplifier PA is adjusted to appropriate servo coefficients (Kl, (
2)/S') is supplied to the servo circuit SC. Furthermore, the output from the servo circuit SC is applied to a piezoelectric transducer TD that is linked to the probe T(ip). Thereby, by keeping the distance between the probe T(ip) and the sample M constant, the tunneling current 1b is kept constant.

On the other hand, attempts have been made to draw turns directly on a silicon substrate using STM. For example, J, Vac,
Sci, T channel, B Vol, 4
kl, Jan/Feb, 1986, M.
A.

It has been reported by M. C. Cord et al. that tracks were carved in a gold vapor-deposited thin film on a silicon substrate after STM scanning at an applied energy of IQeV. Also,
In the same magazine, 2 to lQnm decosenoic LB film
5v.

There have been reports of writing lines with a 12 nA beam.

In addition, Stanford University's C, F, Kuwait,
Dobrik, Albert et al., a 208m×20 piezoelectric material made of Zn20 constructed by IC process.
STM (Micro STM) consists of a sharp probe, which is a vapor-deposited implant, at the tip of a piezoelectric drive cantilever with a size of 0 μm x 5 μm, using a small hole as a mask using the same IC process.
) has been reported.

(Problem to be solved by the invention) As mentioned above, in the peripheral technology environment of STM,
It is well known to write information on a silicon substrate using M, or to read information by trapping charges, etc., and it is possible to configure a memory device using STM. Moreover,
The above cantilever type STM by IC process
The advent of 2009 has made it possible to construct an arithmetic processing device by combining a large capacity storage device consisting of a large number of STMs with other circuits.

SUMMARY OF THE INVENTION An object of the present invention is to provide an efficient scanning tunnel current arithmetic processing device which combines a 37M storage device and a signal processing circuit and is suitable for signal processing of read/write information of a 37M storage device.

(Means for Solving the Problems) In order to achieve the above object, in the scanning tunneling current calculation processing device of the present invention, a cantilever type STM is configured on an IC substrate, and on the substrate,
A reading means for reading information by detecting a change in tunnel current or a change in unevenness on a recording body from a recording body in which information is recorded as a change in tunnel current, an information writing means, ST
In addition to circuits for M cantilever scan synchronization control, etc.
The input/output calculation means, which can easily perform a signal shift operation using a clock, is connected to the reading means and/or the writing means.

(Function) As mentioned above, by combining the 37M storage device and the human output calculation means, both are controlled by a clock and information calculation processing is possible. Analog calculation processing can be performed at high speed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows a scanning tunnel current arithmetic processing device of the present invention. This scanning tunnel current arithmetic processing device includes a first cantilever 11 configured to be scan-driven by a piezoelectric element on a first IC substrate 10, and a first cantilever 11 configured to be scan-driven by a piezoelectric element on a second IC substrate 20, for example. The second cantilever 21 is orthogonal to each other, and the substrates 10 and 20 are arranged one above the other. Further, on the first IC substrate 10, there is a CCD circuit 12, a scanning circuit for the piezoelectric element, and a CCD circuit 12 for scanning the piezoelectric element.
2, and a drive circuit 14 including a preamplifier as shown in FIG. 9, a write circuit, a servo circuit, etc., which will be described later.

Figure 2 shows the above-mentioned item 1. It shows the configuration of the second cantilever 11°21. The first cantilever 11 is provided with a free end region 110 located at its tip, and the second cantilever 21 is provided with a free end region 210 located at its tip. The free end region 110
and 210 are arranged so as to face each other in a vertical relationship, and their overlapping area constitutes a scanning area.

The above-mentioned ml cantilever 11 has a plurality of tunneling current probes 1111° 1112 r ~ on the lower surface of its scanning area.
, 111n are arranged. These probes 1111,
1112. ~． 111n are arranged at predetermined distances in the scanning direction, for example, at intervals approximately equal to the scanning amplitude. In addition, the probes 1111, 11121 to 111
n are also arranged at the same intervals as above in the longitudinal direction of the first cantilever 11.

A recording body (recording medium) 211 is provided on the upper surface of the scanning area of the second cantilever 21 . In this recording medium 211, information corresponding to write data is formed in the form of a molecule-sized grid on the surface of the medium in which, for example, charges or magnetic domains are selected. and,
The probes 1111, 1112. ~, 1lln and record body 2
11 is set to be sufficiently close.

Here, the arrangement of the piezoelectric body and electrodes in the first cantilever 11 will be explained. In the first cantilever 11, two piezoelectric materials (for example, Zn20 layer) 112
a, 112b are upper and lower All! Polar layer 113 (for convenience,
In the drawing, the lower AfI electrode layer 113 is not shown) and the middle AI electrode layer 114 are sandwiched by a plurality of plane patterns, forming three separate and independent piezoelectric actuators.

The first cantilever 11 of the upper and lower Aj7 electrode layers 113
Electrode patterns 113a, 113b, and 113c arranged to divide into thirds in the longitudinal direction form two sets of piezoelectric drive bodies. That is, the electrode pattern 113b (upper and lower Al electrodes 113b).

One pair of cantilevers 113b) expands in the longitudinal direction and contracts the other by applying voltages of opposite phases by the drive circuits 14 connected to each other via lead wires, using the Aj7 electrode layer 114 as a common electrode. This is an electrode for bending in two directions.

In addition, a pair of electrode patterns 113a, 113c (upper and lower one electrode 113g, 113a and Al electrode 113a, 113
One pair c) is an electrode connected to a drive circuit 14 for bending the cantilever 11 in the Y direction.

On the other hand, in the second cantilever 21, Aj electrodes Jl are provided vertically facing each other (for convenience, the lower A in the drawing is
I electrode layer is not shown) 212 electrode patterns 21
2a and 212b sandwich a piezoelectric material (Zn20 layer) 213,
The entire second cantilever 21 is vertically divided into two to form a set of piezoelectric drive bodies. That is, the pair of electrode patterns 212a and 212b (upper and lower Al electrodes 212a)
, 212a and AfI electrode 212b.

A pair of electrodes 212b) are connected to the drive circuit 14, and one of the electrodes is extended in the longitudinal direction and the other is contracted in the longitudinal direction by voltages of opposite phase applied to the respective drive bodies, thereby causing the cantilever 21 to bend in the X direction. be.

In addition, in this embodiment, the tunnel current probe 1
11. ．． 1112. . That is, the pattern size of the IC process corresponds to the scanning amplitude in the scanning direction (Y direction) of the width of the cantilever 11, and the patterns are densely arranged at similar intervals in the longitudinal direction (X direction) of the cantilever 11. It is set up. These tunnel main probes 11
1. ．． 1112. 〜, 1lln is obtained by repeating metal vapor deposition through a mask having a large number of small holes in a lattice pattern.
Formed into a cone shape.

On the other hand, the free end region 211 of the second cantilever 21,
The probes 1111, 1112. A recording body 211 is provided on the surface facing 111n, and this recording body 211
The probes 1111.1112. ~． Each region 2111, 2112 . ~211n
Data is written every time. Note that in this case, the area 211. .

2112, .

The first and second substrates 10 configured in this manner.
20 with the second substrate 2o down and the first substrate 10 up, in the free end region 110.2 of each cantilever 11.21.
An embodiment of the present invention is realized by overlapping the 10 parts in correspondence with each other.

Note that the tunnel current probes 1111 1112, -. 111n to the second cantilever 21,
It is also possible to arrange the recording body 211 on the first cantilever 11. Alternatively, the free end regions 110, 210 of each cantilever 11, 21 can be stacked on top of each other, with the second substrate 20 on top and the first substrate 10 on the bottom.

FIG. 3 shows the COD circuit 12, the control circuit 13, and the FIFO (First 1n-Nrst) described later.
This is a concrete diagram showing the block configuration of the CCD block 121 and S7M shown in FIG.
2 schematically shows a memory block 124 and its peripheral circuit configuration.

In FIG. 3, 121 is a CCD block, which has n surface channel type CCE) arrays 121, . 1212
, 1213. ~． 121n, etc. Each array 121+, 1212+1 of this CCD block 121
213, ~, 121n are controlled by, for example, a three-phase CCD clock generation circuit 122, and transmit information to each CCD output diode 1231, 1232 + 1233, ~
123n is output in parallel. Further, in the CCD block 121, the first half of the array section is a light receiving section 121a, and the second half is a transfer section 121b.
It is said that

On the other hand, 124 is an 87M memory block composed of the plurality of areas mentioned above, and has n S7M units (
area) 211□, 2112°2113, ~, 211n. Each unit 211 of this memory block 124
0,211□.

2113 to 211n are STM scan synchronization control circuits 1;
25, the respective information write circuits 126+, 1262, 1263, . 126n
is controlled, and as a result, the tunneling current probe group 111 (111+
, 1112. 111n) is operated, information is written from a predetermined position.

In addition, each of the above S7M units 2111, 2112°21
13 to 211n are the STM scan synchronization control circuits 1;
A readout control pulse from each readout amplifier 127 . ．． 127□.

127,...,127. is controlled, whereby the corresponding probes of the tunneling current probe group 111 are operated, thereby reading information from a predetermined position. In addition, please write this information.

or reading is performed by CPU1 as the system controller.
mode selection circuit 12 to which a mode signal from 28 is supplied;
9, and an STM block selection circuit 136 to which a block selection signal from CPU 28 is supplied. In addition, each unit 2111.2112 + 211
31~,211. Capacity: 1100 scanning strokes
When n is a density of lnm, there are 10,000 (point) digits in a two-dimensional (x, y) serial recording space.

n COD output diodes 1231, 1232, 123 . , ~123n, and n 87M units 2111°2112.21131~.
A parallel interface circuit 130 connecting the 87M memory block 124 equipped with 211n is a CCCD
At a predetermined timing under the control of the -5T synchronous control circuit 131, the CCD output diodes 1231, 1232.
1233. . . . , 123n to the corresponding information writing circuits 126, . 1262.1
263. ~, 126n. Here, for example, COD transfer speed (fc) and ST
The relationship between M and the writing speed (f t) is an integral multiple (f,
, t −nfc (n is an integer)).

Therefore, each CCD array 1211, 1212.

1213, ~. 121. If the transfer capacity of 1000 (pixel) digits is transferred at a speed of fc-100KHz, in the case of n-10, ft-IMH is transferred during STM scanning.
Writing is performed by the clock of z. At this time, writing is performed in the serial recording space with a 1:10 interleave, and 10 frames of images can be recorded in one STM memory block by 10 parallel transfers.

On the other hand, parallel interface circuit (PIF) 1
32 is the readout amplifier 1271, 1272°127
3, ~. 127. information from the analog bus 133,
Alternatively, the signal is output to a digital bus 135 via an A/D converter 134 as an extension of a switched capacitance circuit, which will be described later.

In addition, the parallel interface circuit 130.132,
and 137, for example, a MOS type switched capacitor circuit (S
C circuit).

In addition, the parallel interface circuit 130.13
2, and 87M memory block 124, the CPU
The selection is made under the control of an STM block selection circuit 136 connected to 128.

Here, the information read operation will be explained with reference to FIG. When reading information, the drive circuit 14 first reads the first . Electrode patterns 113g are arranged on each of the second cantilevers 11°21.

Voltages of opposite phases are alternately applied to 113c, 212g, and 212b. As a result, the first cantilever 11
vibrates in the direction indicated by Y, and the second cantilever 21
vibrates in the direction indicated by X.

At this time, the drive circuit 14 determines the respective periods and synchronizes them, so that the tunnel current probe group 111 (111,
~11 in) scan the recording medium 211 on the free end region 210 of the second cantilever 21 facing each other.

Further, the drive circuit 14 servos the tunnel current from, for example, the central tunnel current probe of the tunnel current probe group 111 (i-n/2), and applies this servo voltage to the electrode pattern 113b of the first cantilever 11. to be applied. This causes the first cantilever 11 to move in the vertical direction.
That is, the tunneling current probe group 111 is driven in the direction shown by 2 in FIG. 2, and the distance between the tunneling current probe group 111 and the recording body 211 is maintained at a predetermined interval.

In this state, the mode selection circuit 129 is controlled by the mode signal from the CPU 128, and the ST
The read control pulse from the M scan synchronization control circuit 125 is
87 selected by the STM block selection circuit 136
M memory block 124 read amplifier group 127 (1
27z to 127n). As a result, the above S
87M selected by the TM block selection circuit 136
While the memory block 124 is scanned by the tunneling current probe group 111 in the direction of arrow i in the figure, information is read by the probes corresponding to each of the 37M units 2111 to 211n.

In this way, during the scanning movement of the probe group 111, tunneling currents from a plurality of probes belonging to the 87M memory block 124 selected by the STM block selection circuit 136 are detected by the readout amplifier group 127. The change in tunnel current is transmitted from the parallel interface circuit 132 to the analog bus 133 or A/D.
It is output to a digital bus 135 via a converter 134. As a result, the recorded information is changed to analog recording data r20.0.5.0.0°1,...'' or digital recording data "160.1.0,0.1.."
It is read as .

Next, the information writing operation will be explained with reference to FIG. When writing information, the tunneling current probe group 111 in the free end region 110 of the first cantilever 11
The recording body 21 on the free end region 210 of the cantilever 21 of
1, the mode selection circuit 129 is controlled by the mode signal from the CPU 128, and the write control pulse from the STM scan synchronization control circuit 125 is applied to the 87M memory block selected by the STM block selection circuit 136. 124 information writing circuit group 126 (1261-126.). As a result, the 87M memory block 124 selected by the STM block selection circuit 136 is scanned by the tunneling current probe group 111 in the direction of the arrow U shown in the figure.
Information is written by a plurality of probes corresponding to each of the 37M units 2111 to 211n.

In this way, during the scanning movement of the probe group 111, the COD output diode group 123 (123, to 123
The information transferred to the parallel interface circuit 130 via n) is transferred to each information writing circuit group 126 (1261 to 1261) at the timing of the COD-STM synchronization control circuit 131.
126n). As a result, each unit 211 is
The above information to be written in 1 to 211n is serially recorded as analog recording data r15.0°10,J or digital recording data r1.0°1,...'', and in total n parallel block recordings are performed. It will be done.

FIG. 7 shows that one of the tunneling current probes is connected to a corresponding 37M unit of 87M memory block 124 (e.g., 87M memory block 124).
It shows an example of information recorded by scanning the M unit 2111). In FIG. 7, the probe moves from the writing start position lSt to a vector u shown by a solid line.
It moves like (x, y) and writes information indicated by dots. In this case, by aligning the direction of the write start position St with the direction of the end position, the time required to return to the write start position (or read start position) St can be shortened.

FIG. 8 shows the movement vector of the probe when reading out the information written as described above.

In this embodiment, when the readout vector is indicated by a dashed line, F I
F O (PIrsL In-First out) or L I F O (Last In-First out)
t) is made possible under the control of the STM scan synchronization control circuit 125. Of course, the above S
Under the control of the TM scan synchronization control circuit 125, it is also possible to return to the starting position St in a shortened manner from the middle of scanning.

As mentioned above, a large capacity storage device consisting of STM,
By combining other circuits, such as a signal processing circuit suitable for processing read/write information signals with the S7M storage device, such as a COD circuit, arithmetic processing can be performed at high speed. That is, in addition to the tunnel current detection circuit, information write circuit, STM scan synchronization control circuit, etc. necessary for the S7M storage device, a COD circuit that can easily obtain a signal shift operation using a clock is added to the tunnel current detection circuit or information write circuit. By arranging them on the same board in a connected state, it is possible to input and output information. Further, after the tunnel current detection circuit, there is a switched capacitance circuit which is also operated by clock operation, and by combining an AND10R circuit from the current circuit which inputs the tunnel current, and further combining this with a signal inversion circuit, it is possible to handle multiple STMs. A logic circuit for outputting information is configured.

The above 87M storage device scans the recording medium at a predetermined scanning speed Vs.
During the movement, the pulse width T
Record the information with d. On the other hand, there are various methods for inputting and transferring information in a CCD circuit, such as three-phase, two-phase, pseudo-phase, and four-phase transfer. Now, assuming that the clock frequency of this CCD circuit is fc and assuming parallel transfer, which is a feature of this invention, one CCD circuit has one 87
When M storage devices are made compatible, serial recording can be performed for each compatible unit. In this way, both devices are controlled by a clock and are also devices that can perform analog processing, so high-speed arithmetic processing can be easily achieved.

That is, in the 87M storage device, analog signal recording using tunnel current can be performed depending on the size of information writing. In addition, since the CCD circuit is also capable of analog signal processing, after the analog input information is transferred and output by the CCD circuit, it can be transferred to the recording medium of the 87M storage device at high speed using a simple interface circuit without using an A/D converter. Analog recording can be performed.

In addition, by combining with the STM recording analog reference signal source circuit, a multi-value logic circuit can be constructed between the above-mentioned circuits.

Furthermore, since the CCD circuit can also have a photosensor function, a multifunctional one-chip processing circuit can be easily constructed from image input to image calculation processing.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the invention.

(Effects of the Invention) As detailed above, according to the present invention, by combining a large-capacity storage device made of STM and other signal processing circuits, signal processing of read/write information of an 87M storage device can be performed. A suitable and efficient scanning tunnel current arithmetic processing device can be provided.

[Brief explanation of the drawing]

FIG. 1 is an exploded configuration diagram of a scanning tunnel current calculation processing device which is an embodiment of the present invention, FIG. 2 is a perspective view showing a cantilever of the scanning tunnel current calculation processing device taken out, and FIG. 3 4 is a block diagram schematically showing the circuit configuration, FIG. 4 is a block diagram showing the overall circuit configuration, FIG. 5 is a diagram for explaining information reading operation, and FIG. 6 is information writing operation. Figure 7 is a diagram showing an example of the scanning of the tunnel current probe during writing and recorded information, and Figure 8 is a diagram showing the scanning of the tunnel current probe during writing and reading. This is a diagram showing an example, and FIG. 9 is a diagram shown for explaining the prior art and its problems. 10... IC board, 11... First cantilever 1
2...CCD circuit, 13...control circuit, 14...
Drive circuit, 20... IC board, 21... second cantilever 111 (111+, 1112.1113.~
111n)...Tunnel current probe, 121...CC
D block, 1211 + 1212 + 1213
, ~121, CCD array, 124-3 TM memory block, 125...STM scan synchronization control circuit,
126 (1261, 1262, 1263, ~126n
...Information writing circuit, 127 (1271゜1272
．． 1273. 〜, 127n)...readout amplifier, 12
8... CPU, 131... CCCD-5T synchronous control circuit, 211... Recording body, 21112112.211
3, ~,2111...57M units (area). Applicant's representative Patent attorney Atsushi Tsuboi Diagram (7' Zotalum Go 1:20 (Analog 1 已钒) Diagram B Gur Butano 4 Self Representation) 15 (7rO'7''!ellt) Figure 6 ( a) Figure 8 (b)

Claims (1)

[Claims] A cantilever body configured on an IC substrate and scanned and driven by a piezoelectric element, a tunnel current probe provided at the tip of the cantilever body, and a tunnel current probe provided opposite to the tunnel current probe. , a recording body on which information is recorded so as to cause a change in tunnel current due to scanning of the probe by relative movement with the probe; a reading means for detecting information and reading information; a writing means for writing information on the recording medium using the tunneling current probe; and an input/output calculation means connected to the writing means and/or the reading means and operated by a clock. A scanning tunnel current arithmetic processing device comprising: a control circuit for driving the piezoelectric element, and controlling the writing means, reading means, and input/output calculating means.