JPH02192171A - Switching element - Google Patents

Abstract

PURPOSE:To obtain a switching element of simple structure which is turned ON or OFF corresponding to ON or OFF of a light beam or an electron beam by a method wherein a superconductor is made to fluctuate in temperature centering about its critical temperature as a light beam or an electron beam is made to serve as an input source. CONSTITUTION:A part or the whole of a conductor is formed of a superconductor 11, which is made to serve as an irradiation section 12 irradiated with a light beam or an electron beam, and the whole conductor is kept at a critical temperature or lower where the superconductor 11 is kept in a superconductive state. When the irradiation section 12 is not irradiated with a light beam or an electron beam, the superconductor 11 is kept at a critical temperature Tc or lower and zero in electrical resistivity, the voltage of a power source 13 does not appear at an output terminal 15. When the irradiation section 12 is irradiated with a light beam or an electron beam, the temperature of the superconductor 11 rises slightly higher than the critical temperature Tc and the superconductor 11 grows to have resistivity, a voltage appears at the output terminal 15. That is, the superconductor 11 functions as a switching element.

Description

[Detailed Description of the Invention] [Summary] Regarding a switching element, particularly a switching element using a superconductor and operated by light or an electron beam, the switching element uses light or an electron beam as an input source and turns it on and off.
The purpose of the present invention is to provide a switching element with a simple structure that utilizes the OFF state, and includes a conductor partially or entirely made of a superconductor whose one end side is connected to a power supply terminal, and a part of the superconductor that is irradiated with light or electrons. It is equipped with a window for irradiating the beam and an output terminal for extracting the voltage at the end of the superconductor to which the light or electron beam is irradiated, and the output voltage can be turned on or off by turning on or off the light or electron beam. The device includes a switching element that turns off and on.

[Industrial application field]

The present invention relates to a switching element, and particularly to a switching element using a superconductor and operated by light or an electron beam.

[Prior Art] Conventional switching elements mainly utilize the switching characteristics of transistors. Those that take voltage as input include, for example, bipolar transistors and field effect transistors, and those that take light as input often use photodiodes as photodetectors.

It is equipped with an output terminal for taking out the voltage at the end of the superconductor to be irradiated,
This problem is solved by a switching element that turns the output voltage on and off or off and on depending on when it is turned off.

[Problem to be solved by the invention]

However, in either case, it is necessary to form a pn junction in the semiconductor, resulting in a complicated structure and cannot be easily manufactured.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a switching element with a simple structure that uses light or electron beams as an input source and utilizes the on/off operation of the light or electron beams.

[Means to solve the problem]

The above problem consists of a conductor partially or entirely made of a superconductor whose one end side is connected to a power supply terminal, a window for irradiating a part of the superconductor with light or an electron beam, and a window for irradiating the light or electron beam ( [Operation] Fig. 1 is an explanatory diagram of the principle of the present invention. In the figure, a conductor partially or entirely made of a superconductor 11 serves as an irradiation part 12 to which light or electron beam is irradiated. One end of the superconductor 11 is connected to a power source 13 via a protective resistor 14, the other end is grounded, and an output terminal 15 is provided for taking out the terminal voltage of the superconductor 11. , the entire superconductor 11 is maintained below a critical temperature at which it exhibits superconducting properties.That is, in the present invention, when not irradiated with light or electron beam,
Since it is maintained at a temperature that exhibits superconducting properties, it is maintained at a temperature (a) below the critical temperature Tc, as shown in FIG. 3, and its electrical resistivity becomes 0. Therefore, the equivalent circuit configuration shown in FIG. 2(a) is obtained, and the voltage of the power supply 13 does not appear at the output terminal 15. On the other hand, when irradiated with light or an electron beam, the temperature of the superconductor 11 rises to a temperature (b) slightly higher than the critical temperature Tc and reaches 0. It has an electrical resistivity of several Ωcm. Therefore, the configuration of the equivalent circuit shown in FIG. 2(b) is obtained, and if the voltage of the electric TX 13 is E, the resistance value of the resistor 14 is Ro, and the resistance value of the superconductor 11 is RI, the output terminal 15 has the following: V,=R.

A voltage of /(Ro+R+)·E appears. Since the entire structure is cooled to a temperature at which a superconducting state occurs, when the irradiation with light or electron beam is stopped, the superconductor 11 returns to the superconducting state and the output voltage becomes zero. That is,
Operates as a switching element.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to an illustrated embodiment.

FIG. 4 is a partial perspective view of the superconductor of the switching element according to the first embodiment of the present invention, and FIG. 5 is a sectional view of the switching element of FIG. 4.

In these figures, an insulating film 22 such as an oxide film is formed on a silicon substrate 21, and a substantially T-shaped conductor pattern made of an oxide superconductor 23 is formed on this insulating film 22. The oxide superconductor 23 is covered with an insulating film 25 made of an oxide film, etc., except for the light irradiation part 24.
Further, in order to prevent light from being irradiated to areas other than the light irradiation section 24, a light shielding film 26 is covered on the insulating film 25. That is, a window 27 is formed on the light irradiation section 24 through which the light shielding film 26 and the insulating film 25 are opened to allow light to enter. One side of the oxide superconductor 23 is connected to a power source (not shown), the other end is grounded, and the center of the T-shape is an output terminal for taking out the voltage at the end of the oxide superconductor 23 to the outside. All of these are maintained at a temperature slightly lower than the critical temperature at which the oxide superconductor 23 exhibits superconducting properties.

In the switching element having the above configuration, when the oxide superconductor 23 is not irradiated with light, the oxide superconductor 23 is maintained in a superconducting state, so that the resistivity becomes O and no voltage from the power source appears at the output terminal. On the other hand, light passes through the window 27 into the oxide superconductor 2.
When the light irradiation section 24 of No. 3 is irradiated with light, the temperature of the irradiated light irradiation section 24 rises and has a predetermined electrical resistivity, and a voltage from the power source appears at the output terminal. Since the entire structure is cooled below the critical temperature at which a superconducting state occurs, when the light irradiation is stopped, the superconducting state is restored and the output voltage becomes O. That is, it operates as a switching element in which the voltage at the output terminal is turned on and off by turning on and off light.

FIG. 6 is a sectional view of a switching element according to a second embodiment of the present invention, and FIG. 7 is an enlarged view of portion A in FIG. 6.

In these figures, an insulating film 32 such as an oxide film is formed on a silicon substrate 31, and a metal film 33 forming a cathode made of a material such as aluminum (A) or tungsten (W) is formed on this insulating film 32. An insulating film 34 such as an oxide film is formed on this metal film 33, and a metal film 35 forming a grid made of materials such as L and U is further formed in this insulating film 34. A groove 36 is formed by opening a part of the insulating film 34 and the metal film 35, and a fine electron gun 37 having a thin tip is formed on the metal film 33 at the bottom of the groove 36.As a fine electron gun. For example, the one made by Philips Research Laboratory in the Netherlands is known.
The life of the B-packing device was short because ions collided with the electron gun and damaged the tip, but this microelectron gun has many parts hidden by the metal film 35 that forms the grid, so fewer ions collide and it can be expected to have a long life. .

Then, a substantially T-shaped conductor pattern made of an oxide superconductor 38 is formed on the insulating film 34 so as to cover the groove 36. Then, a negative on/off signal is inputted to one metal film 33 and a positive on/off signal corresponding to the input signal is inputted to the other metal film 35. That is, the portion of the oxide superconductor 38 facing the window 39 at the top of the groove 36 forms an anode and serves as a portion 40 irradiated with electrons from the microelectron gun 37.

In the switching element having the above configuration, the microelectron gun 37 is an electron gun that emits electrons from its tip by an electric field, and when an input voltage is applied to the metal film 35 forming the grid, an electron beam is emitted from the microelectron gun 37. collides with the oxide superconductor 38 forming the anode, and this part (
The temperature of the irradiation section 40) is increased. As a result, the oxide superconductor 38 portion has electrical resistivity, and the voltage from the power supply appears at the output terminal as in the above-described embodiment. Since the entire structure is cooled below the critical temperature at which a superconducting state occurs, when the voltage application is stopped, the electron beam is no longer emitted and the superconducting state is restored again, and the output voltage becomes O. That is, it operates as a switching element in which the voltage at the output terminal is turned on and off by turning on and off the electron beam. In this example,
Since an output voltage is obtained by using a voltage as an input, it is easy to use the output of a negative element as an input of another element, which is suitable for integration.

Note that although oxide superconductors 23 and 38 are used in the above embodiments, the scope of application of the present invention is not limited thereto, and can be applied to other types of superconductors.

〔Effect of the invention〕

As explained above, according to the present invention, the superconductor is turned on and off in response to the on/off of the light or electron beam by changing the temperature above and below the critical temperature using light or an electron beam as an input source. A switching element with a simple structure can be obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the present invention, Figures 2 (a) and (b) are equivalent circuit diagrams of the present invention, Figure 3 is a diagram showing the resistance-temperature curve of a superconductor, and Figure 4 is a diagram of the present invention. FIG. 5 is a sectional view of the first embodiment of the invention, FIG. 6 is a sectional view of the second embodiment of the invention, and FIG. 7 is the same as that of FIG. 6. It is an enlarged sectional view of A part. In the figure, 11 is a superconductor, 12 is an irradiation part, 13 is a power supply, 14 is a resistor, 15 is an output terminal, 21 is a silicon substrate 22, 25 is an insulating film, 23 is an oxide superconductor, 24 is a light Irradiation part, 26 is a light-shielding film, 27 is a window, 31 is a silicon substrate, 32.34 is an @edge film, 33.35 is a metal film, 36 is a groove, 37 is a microelectron gun, 38 is an oxide superconductor , 39 is a window, and 40 is an irradiation part. ”

Claims (1)

[Claims] a conductor partially or entirely made of a superconductor (11), one end of which is connected to a power supply terminal; a window for irradiating a part of the superconductor (11) with light or an electron beam; A superconductor (1
1) A switching element characterized in that it is equipped with an output terminal (15) for extracting the voltage at the end to the outside, and that the output voltage is turned on and off by turning on and off the light or electron beam.