JP2001298201A - Semiconductor control circuit element and electric circuit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor control circuit element which can control an electric circuit at a high speed, by quickly and remarkably changing only a part of the resistance of the element subjected to light or electric-field application, and also to provide an electric circuit using the element. SOLUTION: Heavy metal that forms an acceptor level, e.g. Au 3, is doped in at least part of a semiconductor layer 2 which is doped, e.g. with n-type impurities. The doping of the heavy metal layer 3 causes the n-type impurities in the doped part to be cancelled and to become high in resistance. And electrodes 5 and 6 are formed at both faces of the semiconductor layer 2 so that an electric field can be applied to the layer 2, or light can be irradiated thereon. The voltage application or light irradiation causes the heavy metal to be excited so that the resistive value of the semiconductor layer can be abruptly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes a property that a heavy metal doped in a semiconductor is excited by light or an electric field to change the resistance of the semiconductor layer and change the electric or magnetic field pattern in the semiconductor layer. The present invention relates to a semiconductor control circuit element that can be used for switching of a circuit and a change in characteristics of a circuit element, and an electric circuit using the same.

[0002]

2. Description of the Related Art Conventionally, an electric circuit is controlled by light, for example, by Yasushi Horii and Makoto Tsutsumi in "Optical control of semiconductor substrate microstrip comb-shaped gap to which bias voltage is applied" (The Institute of Electronics, Information and Communication Engineers, 1998). It is disclosed that by exciting high-resistance silicon with light and bringing the silicon itself into a plasma state, the electrical resistance can be reduced and the electrical circuit can be controlled.

[0003]

In the above-described method of changing the electrical resistance by directly exciting silicon and creating a plasma state, it is difficult to control an electric circuit at high speed because the lifetime of the plasma is long. Further, since the plasma state can be generated only on the surface, there is a problem that the control range is narrow.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to control an electric circuit at high speed by rapidly and largely changing the resistance of only a portion to which light or an electric field is applied. It is an object of the present invention to provide a semiconductor control circuit element capable of performing the following.

Another object of the present invention is to provide a structure capable of efficiently irradiating the semiconductor control circuit element with light or applying an electric field.

Still another object of the present invention is to provide an electric circuit using the semiconductor control circuit element and capable of easily changing characteristics such as switching, circuit switching, phase and circuit constant, and a specific circuit configuration thereof. It is in.

Still another object of the present invention is to provide a controllable high-frequency transmission line, a high-frequency circuit element, an electric circuit element, and the like using the semiconductor control circuit element.

It is still another object of the present invention to provide an optical microwave conversion circuit capable of converting an optical signal into a microwave signal.

[0009]

A semiconductor control circuit device according to the present invention comprises a semiconductor layer doped with an n-type or p-type impurity, at least a portion of the semiconductor layer being doped, and a heavy metal that cancels out n-type or p-type impurities to increase the resistance and is irradiated with light having a wavelength shorter than the wavelength capable of exciting the heavy metal and longer than the wavelength capable of exciting the semiconductor layer, or Is applied, the heavy metal is excited, and the resistance of the semiconductor layer can be reduced.

With this configuration, in a normal state, the resistance is increased by doping with a heavy metal.
Acting as a dielectric layer, when light or an electric field is applied,
Since the heavy metal is excited, the n-type or p-type impurity which is first doped in the semiconductor layer acts as a dopant, and has a very low resistance. The heavy metal can be excited in a much shorter time than in the above-described conversion of silicon itself to plasma, and can be in a low-resistance state. The phenomenon that a low resistance state can be obtained within this short time is
Generally, deep acceptor levels are based on the property of trapping carriers at a very high speed in the picosecond order.
Therefore, it is possible to respond in a nanosecond order even to a portion to which light or an electric field is applied.

The amount of the n-type or p-type impurity to be doped is 1 × 10 ¹⁷ to 1 × 10 ¹⁴ cm ⁻³ , and the amount of the heavy metal to be doped is substantially equal to the amount of the n-type or p-type impurity. Thus, switching between high resistance and low resistance can be easily performed. In addition, since the n-type impurity forms an acceptor level with a heavy metal, a large change in resistance is preferable.

The semiconductor layer is made of an elemental semiconductor, the heavy metal is at least one metal selected from the group consisting of gold and platinum, or the semiconductor layer is made of a compound semiconductor or an alloy semiconductor, and the heavy metal is an iron group. At least one metal selected from the above metals is preferable because the change in resistance can be particularly increased.

Here, the metals of the platinum group include Pt, Ir, R
u, Pd, Os, Rh, and the like;
It means Cr, Mn, Ni, Co and the like.

It is preferable that a conductor layer, an insulator layer, or a composite layer thereof is provided with good adhesion on at least one surface side of the semiconductor layer, so that a bonding surface having no electrical gap can be obtained. To be provided with good adhesion means to be provided electrically without any gap, and is provided by a method such as sputtering, deposition such as vacuum evaporation, CVD, or plating.

If the conductor layer, the insulator layer, or a composite layer thereof is made of a material having at least a transmittance to a wavelength of light capable of exciting the heavy metal, the conductor layer or the insulator layer is formed. Light can be applied to excite the heavy metal to simplify the structure, which is preferable. Here, having at least transmissivity means that it is not necessary for the light of the wavelength to be completely transparent, but it is sufficient to transmit a part of the light.

By doping the heavy metal only in the vicinity of the surface of the semiconductor layer, the semiconductor layer not doped with the heavy metal can be used as a conductor layer.

One end of an optical waveguide to which a light emitting source can be connected at the other end is abutted against or pierced into the surface of the semiconductor layer, or When the light-emitting element is provided through the conductor layer or the insulator layer, the structure can be irradiated with the light, so that the heavy metal of the semiconductor layer can be efficiently irradiated with the light.

The optical waveguide comprises a planar optical waveguide or an optical fiber, and a refractive index of light by a filler in the optical waveguide has a constant distribution in a direction perpendicular to a traveling direction of the light. Is preferred. With this structure,
The radiation loss of light transmitted through an optical waveguide or an optical fiber can be reduced, and the radiation emitted therefrom is focused in a semiconductor layer, thereby reducing the radiation loss of light from within the semiconductor layer. be able to. As a result, light propagates in the semiconductor layer over a long distance, and light can be efficiently radiated to heavy metal in the semiconductor layer at a required location.

A conductor is provided on both the upper and lower surfaces of the semiconductor layer, and the conductor is used as both electrodes, so that the electric field can be applied. can do.

The electric circuit according to the present invention is characterized in that the semiconductor control circuit element according to claim 1 is an electric circuit for handling an electromagnetic wave including a direct current which is longer than a wavelength of exciting the heavy metal of the semiconductor control circuit element. It is inserted so as to be affected by a change in the resistance value of the semiconductor layer. That is, the above-described semiconductor control circuit element is inserted into a normal DC circuit, an AC circuit, a high-frequency circuit such as a microwave or a millimeter wave, a circuit in an optical region having a wavelength longer than the wavelength that excites heavy metals, and the like. Can be controlled by light or an electric field.

Specifically, an electric network or a control network is formed on the semiconductor control circuit element directly or via an insulating film, or on an insulating substrate on which the semiconductor control circuit element is formed. The circuit elements of the net can be configured to be controllable by irradiating the light or applying an electric field.

The electric circuit may be an MIC, a coplanar circuit,
A high-frequency circuit having at least one of an NRD guide (non-radiative dielectric waveguide), a coaxial line, a lumped-constant circuit, and a resonator is particularly difficult to control. Can be easily controlled.

The electrode for applying an electric field for exciting the heavy metal of the semiconductor control circuit element is coupled to the high-frequency circuit element via a choke structure, so that the electromagnetic wave does not leak and the like. A control element can be inserted into the.

A transmission line having a branch portion is formed on one surface side of the semiconductor control circuit element, and on / off of the line of the branch portion is controlled by the semiconductor control circuit element, so that a circuit switch is provided in the electric circuit. , Phase shifter, variable resistor,
In addition, the resonator and the like can be easily configured.

In this case, the place where the light for controlling the on / off is irradiated or the electric field is applied is an odd multiple of λ / 4 (λ is the wavelength of the electromagnetic wave transmitted through the transmission line) from the branch point. , The line can be completely open, so that circuit switching, phase change of transmission signal, resistance change of transmission line, etc. can be performed without completely affecting the circuit. Can be.

A conductor is provided along at least upper and lower surfaces of the semiconductor control circuit element according to claim 1 to form a transmission path for electromagnetic waves, and the semiconductor control circuit element is inserted in the middle of the transmission path. Thereby, a waveguide such as an NRD guide or a waveguide can be formed.

Further, the circuit element is formed by providing a conductor film on at least one surface side of the semiconductor control circuit element according to claim 1, so that the semiconductor control circuit element is irradiated with light or an electric field is applied thereto. An electric circuit element capable of changing the characteristics of the circuit element is obtained.

Further, by connecting the semiconductor control circuit element capable of irradiating light according to claim 1 in the middle of the microwave transmission line, an optical microwave conversion circuit capable of converting an optical signal into a microwave signal is provided. Can be configured.

[0029]

Next, a semiconductor control circuit device according to the present invention will be described with reference to the drawings. The semiconductor control circuit element according to the present invention has at least a part of a semiconductor layer 2 doped with an n-type impurity, as shown in FIG. Is doped with heavy metal 3 constituting the acceptor level, for example, Au. The doping of the heavy metal 3 cancels out the n-type impurity in the doped portion, thereby increasing the resistance. And FIG.
In the example shown in (c), the metal film 5 is formed on the front side and the back side.
a, 6 are provided, and an electrode 5 and a back electrode 6 are formed on a part of the front surface side and separated from other parts, respectively.
The configuration is such that an electric field can be applied to the That is, by applying an electric field to excite the heavy metal, the n-type impurity which is doped first acts, and the resistance of the semiconductor layer 2 is rapidly reduced.

In order to manufacture the semiconductor control circuit element 1, first, as shown in FIG.
1Ω · made of a semiconductor substrate having a thickness of about 100 to 1 mm
Au on one surface of the n-type single crystal silicon semiconductor layer 2 of about cm.
Alternatively, Pt is formed by sputtering or vacuum evaporation. This film is deposited so that Au diffused into silicon in a later diffusion step is about 1 × 10 ¹⁶ cm ⁻³ . Then, by keeping the semiconductor layer 2 at about 300 to 1300 ° C. in a reducing atmosphere or an inert atmosphere, Au 3 is diffused into the silicon semiconductor layer 2 as shown in FIG. As a result, Au is doped into the semiconductor layer to increase the resistance.

Thereafter, a conductive metal is formed on the front and back surfaces of the semiconductor layer 2 by sputtering or the like, and only the center portion is separated from the surrounding metal film 5a on the front surface side to form the electrode 5, and the back surface is the entire surface. Is used as an electrode 6 so that an electric field can be applied between both surfaces. It is necessary to form the metal film so as to form a bonding surface where there is no electric gap between the metal film and the semiconductor layer. The metal film is preferably formed by sputtering as described above. Similarly, a bonding surface with no gap can be obtained by electroplating or the like. Further, this metal film is made of a semiconductor layer S
It is preferable to use a metal that is as soft as possible so that mechanical stress can be alleviated with i and a difference in coefficient of thermal expansion can be absorbed.

Then, as shown in FIG. 1D, a conductor plate 7 is provided on the upper and lower surfaces with solder, conductive paste,
Joining by crimping or brazing. The upper surface electrode 5 includes
An extraction electrode 8 is provided, and a portion of the conductor plate 7 is formed as a through-hole. In order to prevent microwave leakage from the portion, λ / 2 (λ is the wavelength of the electromagnetic wave to be transmitted) is used. The length is undercut to form a chalk structure. As a result, an NRD guide is formed, and the microwave transmitted in the transmission path sandwiched between the conductor plates 7 can be controlled by an electric field as described later.

In the example shown in FIG. 1, the electrodes 5 and 6 are formed on both surfaces of the semiconductor layer 2 in order to excite the heavy metal by applying an electric field. Light with a wavelength shorter than the wavelength that can be excited and longer than the wavelength that can excite the semiconductor layer 2 may be applied. FIG. 2 shows an example of an NRD guide configured to irradiate this light. That is, a through-hole is provided in the metal film 5a on the upper surface of the semiconductor layer 2 and the tip of the optical fiber 10 is inserted into the through-hole so as to abut the semiconductor layer 2 or to penetrate the semiconductor layer 2 within λ / 4. It is fixed to the plate 7. The conductor plate 7 is electrically connected to the metal films 5a and 6 on the upper and lower surfaces in the same manner as described above, thereby forming an NRD guide. In this case, since the optical fiber 10 is sufficiently thin compared to the wavelength of the microwave and the like, and there is no problem of electrical short-circuit even when it comes into contact with the metal film 5a or the conductor plate 7, almost no electromagnetic wave leaks. And it is not necessary to form a choke structure.

As the semiconductor layer, elemental semiconductors such as Si and Ge, GaAs, GaP, InP, GaN, Si-G
e (silicon germanium), AlGaAs, GaAl
A compound semiconductor such as P, InGaP, GaInN, or GaAlN or an alloy semiconductor can be used. These semiconductors may be single crystal, polycrystal, amorphous, or the like. Regarding the impurity doped into the semiconductor layer 2, the n-type impurity forms an acceptor level with a heavy metal, and therefore has a large resistance change. Therefore, the p-type impurity-doped semiconductor layer 2 is also shown in FIG. As shown, the resistance can be changed rapidly and can be used as well.

As the heavy metal, in the case of an elemental semiconductor, A
Platinum group metals such as u, Pt, Ir, Ru, Pt, Os, and Rh are preferable because they have an appropriate acceptor level depth and can be uniformly doped, and in the case of a binary semiconductor, Cr,
Iron-based metals such as Ni, Fe, Mn, and Co are preferable for the same reason as in the case of the elemental semiconductor.

Next, an example in which the semiconductor control circuit element 1 according to the present invention changes the impedance of a microwave transmission line or the like and converts light or an electric signal into a microwave signal by doping Au into n-type Si. The explanation is given below.

It has long been known that when Au is diffused into Si, its resistance value starts to rise sharply. n
FIG. 12 shows the resistance change when Au is diffused into the p-type Si and Au is diffused into the p-type Si. As is clear from FIG. 12A, 1 Ω · cm n-type Si (FIG.
(A) F: 5 × 10 ¹⁵ cm ⁻³ ) and 1 × 10 ¹⁶ cm
^When Au of ⁻³ is diffused, it rises to 5 × 10 ⁵ Ω · cm. The dielectric relaxation frequency f _d of Si alone is given by equation (1). In FIG. 12, (a) shows n-type Si doped with P (phosphorus), and (b) shows p-type Si doped with B (boron).
Shows the change in resistivity with respect to the amount of Au doping.
J is the n-type and p-type impurity concentrations (cm ^-3 ), respectively.
Is 1 × 10 ¹⁴ , 2 × 10 ¹⁴ , 5 × 10 ¹⁴ , 1 × 10 ¹⁵ ,
2 × 10 ¹⁵ , 5 × 10 ¹⁵ , 1 × 10 ¹⁶ , 2 × 10 ¹⁶ , 5
× 10 ¹⁶ , 1 × 10 ¹⁷ .

F _d = 1 / (2πε ₀ ε _r ρ) (1) where ε ₀ is the dielectric constant in vacuum (8.854 × 10
^-12 (F / m)), ε _r is the relative permittivity, and ρ is the resistivity (Ω ·
m) are shown.

If the relative dielectric constant ε _r = 12 and the resistivity ρ = 5 × 10 ³ Ω · m of Si are substituted, the dielectric relaxation frequency f _{d at} this time becomes 0.3 MHz. Therefore, if it has such a specific resistance, it can be sufficiently used as a dielectric at a frequency of GHz or more, and can be used even at several hundred MHz if some dielectric loss is prepared. In addition, it can be used as a dielectric at direct current and low frequency where the frequency is low and dielectric loss is not a problem. Therefore, it can be seen that Si having the above resistance value can be used as a DC, low-frequency, and high-frequency transmission line.

Next, the absorption wavelength in the light region of the semiconductor substrate in which Au is diffused in Si is given by the following equation (2).

Absorption wavelength = 1 eV / (acceptor level) × 1.2396 μm (2) The acceptor level of Au in Si is 0.5 from the conductor.
Since it is formed at a range of 4-0.53 eV, when 0.53 eV is substituted as the acceptor level in the equation (2), 2.3 μm is obtained as an absorption wavelength when Au is diffused into Si. . Therefore, when light having a wavelength longer than 1.2 μm and shorter than 2.3 μm is irradiated, Au is excited, and the resistance of Si rapidly decreases from 5 × 10 ⁵ Ω · cm to the initial value of 1 Ω · cm. become. For example, the wavelength of a semiconductor laser that is universally used in optical communication is about 1.5 μm, and when this is irradiated into the above-mentioned Si, the resistance of the semiconductor layer sharply decreases. Thus, it is possible to control the high frequency transmitted in Si.

Similarly, as a method for exciting Au, the electrodes 5 and 6 provided on both surfaces of the semiconductor layer 2 use 10 ⁵ V
/ Cm or more can be excited by applying an electric field of not less than 5 × 10 ⁵ Ω.
· Cm, it can be rapidly reduced to about 1 Ω · cm in the initial stage.

According to the present invention, since the capture cross section of Au is large, the capture speed is very fast and almost no excitation time by light or electric field is required. A high-speed electric signal applied to an electrode provided in the semiconductor layer can be followed, and high-speed high-frequency control can be performed.

When a signal is applied to the electrodes 5 and 6 provided on both surfaces of the semiconductor layer 2 by an external electric circuit (not shown) in the NRD guide as shown in FIG. The heavy metal is excited, the resistance at that portion drops sharply, and the microwave is reflected and the transmission loss increases in proportion to the voltage applied to the electrode, so that the microwave can be controlled by the voltage.

In this case, the connection of the electrode 5 at the position of the maximum point of the microwave electric field, which is transmitted through the NRD guide, modulates the microwave with respect to the electric signal supplied by the external electric circuit. The signal is maximized, and the microwave can be sufficiently controlled even for a small external signal. However, if a sufficiently large external signal is obtained, it is not always necessary to provide an electrode at the position of the maximum point of the microwave electric field. Conversely, when the electrode 5 is formed at a position deviated from the position of the maximum point of the microwave electric field, a short circuit occurs under the electrode 5 and the cross-sectional area of the semiconductor layer is equivalently reduced. Can be adjusted.

Further, the NRD as shown in FIG.
When the guide is irradiated with light having a wavelength of 1.5 μm, which is generally used for long-distance transmission using an optical fiber, heavy metals in the semiconductor layer are excited, the resistance is rapidly reduced, and microwaves are emitted. Short-circuits the maximum point of the microwave electric field transmitted through the semiconductor layer, thereby preventing microwave transmission. That is, the signal of the optical fiber can be converted into a microwave, and an optical / microwave converter can be obtained. In this case, similarly to the position of the electrode 5 described above, if the position of the optical fiber 10 is provided at the maximum position of the microwave electric field, the microwave can be modulated by the smallest external signal. Is not necessarily the maximum position of the microwave electric field, and there are cases where it is better to displace them, as in the case of phase adjustment.

FIG. 3 shows an example in which the microstrip circuit is controlled by an external electric circuit. That is, the structure in which the metal film 6 is provided on the back surface of the semiconductor layer 2 made of Si and the conductor plate 7 is further provided on the metal film surface is the same as the example shown in FIG. However, a metal film is patterned on the surface side of the semiconductor layer 2 so as to form the strip line 5b, and a part of the strip line has a half wavelength (λ) length so as not to affect the strip line 5b. The cut-out electrode 5 is formed, a choke structure 9 is provided so as to be electrically connected to the electrode 5, and an electrode 8 for inputting an external signal is formed on the end side. In this structure, when an electric field is applied to the electrode 5 by an external signal, as described above, the resistance of the semiconductor layer 2 sharply drops, and short-circuits with the lower conductor plate 7, thereby controlling the transmission of the strip line. can do.

FIG. 4 shows an example in which a microstrip line is controlled in the same manner as in the example of FIG. 3, in which a switch is formed. That is, a branch circuit (distributor) 5c is formed in the strip line 5b, and the electrodes 5 are provided on the lines branched by the branch circuit 5c in the same manner as in the example shown in FIG. Thus, an electrode 8 for inputting an external signal is formed. This electrode 5 is connected to a branch circuit 5
Since it is formed at a distance of λ / 4 from c, when the semiconductor layer 2 is short-circuited by an external signal, the strip line is opened, which is equivalent to the line being separated from the transmission line. Therefore, the microwave can be transmitted only through the line to which no voltage is applied, and can be operated as a switch by an external signal. Although the two-branch distributor is shown, it is needless to say that the distributor may have three or more branches.

FIG. 5 shows an example in which a phase shifter is similarly formed on a strip line, and an example in which an optical fiber is used for exciting heavy metals. Two types of optical fiber connection methods are shown. That is, the strip line 5b is
A short-circuit point by an optical fiber is provided at a position of λ / 4 · N (λ is a wavelength and N is an odd number) from each branch point of the branched lines 5b and 5d. as a result,
Of the straight line 5b and the ladder-type line (detour path) 5d, the line short-circuited by light irradiation becomes open, and the microwave signal is transmitted through the other line, as in the example shown in FIG. As a result, a phase difference based on the line length difference can be generated.

The optical fibers 13a and 13b are connected to the bypass line 5
d, it penetrates through the strip line 5d and penetrates into or into the surface of the semiconductor layer 2 so that the semiconductor layer 2 can be irradiated with light. The optical fiber 13c has a structure in which the optical fiber 13c can penetrate the conductor layer 7 and the metal film 6 from the rear surface side of the semiconductor layer 2 and abut or slightly penetrate the semiconductor layer 2 to irradiate light. Has become. Either of these structures can be adopted. In short, it is only necessary to irradiate the semiconductor layer below the strip line with light so as to excite the heavy metal and reduce the resistance of the semiconductor layer. When the method of irradiating light is used in this manner, the strip line does not need to be cut out at a length of 波長 wavelength as in the case of the above-described electrode formation, so that there is no variation in circuit constant.

Also in this example, since a short circuit point by an optical fiber is provided at a distance of λ / 4 · N (N is an odd number), the line can be cut off, so that a plurality of ladder-like circuits are formed. Of course, the amount of phase shift can be arbitrarily adjusted. Further, a phased array antenna can be configured by attaching an antenna to the tip of the phase shifter and arranging a plurality of antennas.

FIG. 6 shows an example in which a variable resistor is formed on a strip line. That is, the strip line has the distributors 5c formed at two places as in the example shown in FIG. 5, but in this example, the branching sections 5c are arranged such that the input side and the output side are point-symmetrical. Are formed. In other words, the length of each line is the same regardless of which line is transmitted, and no phase shift occurs. However, in this example, the resistor 15 is loaded on one of the strip lines 15b to form a resistance line. Therefore, when passing through the resistance line 15b, an insertion loss occurs, and the insertion loss can be generated depending on which line is in a conductive state. By connecting a number of these circuits in series and selecting the line, an arbitrary insertion loss can be generated, and the circuit can be operated as a variable resistor.

In this example, as a method of exciting the heavy metal doped in the semiconductor layer, a method of applying a voltage instead of irradiating light is used.
In this case, instead of cutting out a part of the above-mentioned strip line with a length of 波長 wavelength, the strip line 5b is thinned to form the electric field application electrode 5e. The external signal input electrode 8 is formed on the electric field application electrode 5e via the choke structure 9, as in the above-described example.

FIG. 7 shows a coplanar (coplanar) circuit in which an earth line 5a and a signal line 5b are provided on one surface side.
This is an example formed on the surface of a semiconductor (polycrystalline) layer 16 similar to that described above. Reference numerals 5a and 5b denote electrodes (lines) constituting a coplanar circuit, two outer electrodes being ground lines, and a central electrode 5b being a signal transmission line. In the example shown in FIG. 7, polycrystalline silicon doped with an n-type impurity so as to have a low resistance is formed on a light-transmitting substrate 17, and the semiconductor layer 16 is doped with gold to have a high resistance. ing. In this structure, it is necessary not to excite a vertical region below the electrode but to excite in a lateral direction, so it is necessary to excite over a wide area, and without using an optical fiber, As shown in FIG. 7, light is irradiated over a wide range from the lower surface via the transparent substrate. However, light may be irradiated from the lateral direction. In that case, a substrate that does not transmit light may be used instead of the light-transmitting substrate.

According to this structure, when light is irradiated, gold, which is a heavy metal, is excited to be in a plasma state as described above, and the resistance of the semiconductor layer is rapidly reduced. Therefore, the impedance under the signal transmission path changes, and electric signals can be controlled.

The example shown in FIG. 8 is an example of a variable capacitor, in which a semiconductor layer 16 made of polycrystalline silicon doped with an n-type impurity to have a low resistance is formed on a conductive substrate 17. The semiconductor layer 16 is doped with gold to increase the resistance. Then, the surface and side surfaces thereof are oxidized, or an insulating material is provided by sputtering or the like, whereby an insulating film 19 is formed, and the electrode 5 is formed thereon. With this structure, when a voltage is applied between the electrode 5 and the substrate 17, when the semiconductor layer has a high resistance, it acts as a dielectric, and when the semiconductor layer is irradiated with light and has a low resistance, the apparent electrode 5 and the substrate 17 have a low resistance. And the distance between
The capacitance increases. Thereby, it can be used as a variable capacitance element.

FIG. 9 shows an example applied to a variable inductance element. That is, a semiconductor layer 16 made of polycrystalline silicon doped with an n-type impurity to have a low resistance is formed on a substrate 17 made of a ferrite substrate or an insulating substrate, and the semiconductor layer 16 is doped with gold. And high resistance. An insulating film 19 is formed on the upper surface or the entire surface of the semiconductor layer 16, and the metal film provided on the surface is patterned into a coil shape,
An inductor 20 is formed. This inductor 20 is produced in a plurality of arbitrary places as needed,
They can also interact.

With this structure, when the light 18 is not irradiated, the magnetic flux generated by the inductor 20 passes through the semiconductor layer 16 and reaches the substrate 17. The resistance of the layer 16 is reduced, and the change in the magnetic field generated by the inductor 20 causes the semiconductor layer 16 to have a low resistance.
Current flows through it and operates to reduce inductance. As a result, it can be used as a variable inductance element.

FIG. 10 shows an example applied to a switch circuit. That is, as described above, a semiconductor layer 16 made of polycrystalline silicon doped with an n-type impurity to have a low resistance is formed on an insulating or conductive substrate 17, and gold is deposited on the semiconductor layer 16. The resistance is increased by doping. A plurality of electrodes 5 and 6 are formed on the surface, and the optical fiber 10 is provided on the side surface of the semiconductor layer 16 by abutting.

With this configuration, the optical fiber 1
When light is not irradiated from 0, the electrodes 5 and 6 or the electrodes and the substrate 17 are insulated, but the optical fiber 10
When more light is irradiated, the semiconductor layer 16 in the irradiated portion is irradiated.
Is reduced in resistance, and conduction between the respective electrodes 5 and 6 or between the respective electrodes 5 and 6 and the substrate 17 is achieved. The entire surface of the semiconductor layer 16 may be irradiated with light to reduce the resistance of the whole, but if necessary, only part of the semiconductor layer 16 may be irradiated with light to partially short between the electrodes or only between the electrodes and the substrate. It is also possible to conduct only necessary parts. Since partial conduction can be achieved as described above, the switch can also be operated as a multi-contact switch.

FIG. 11 is a diagram showing an example applied to a waveguide. That is, as described above, the conductive substrate 17
A semiconductor layer 16 made of polycrystalline silicon doped with an n-type impurity to reduce the resistance is formed thereon, and the semiconductor layer 16 is doped with gold to increase the resistance. The periphery is covered with the conductor film 21. As a result, a waveguide is formed in which the periphery of the high-resistance semiconductor layer 16 is surrounded by the conductor film 21 having a rectangular cross section. As a result, when the light 18 is not irradiated, the semiconductor layer 16 operates as a normal waveguide, and when the light 18 is irradiated, the resistance of the semiconductor layer 16 is reduced, and the impedance in the waveguide rapidly decreases. Then, the electromagnetic wave propagating in the waveguide is reflected and greatly attenuated. Due to such operation, it can be operated as a waveguide switch and attenuator.

The circuits shown in FIGS. 3 to 6 can be constituted by the waveguide shown in FIG. FIG.
Can be used as a coaxial line.

[0063]

According to the semiconductor control circuit element of the present invention,
Since the resistance value of the semiconductor layer can be switched at high speed between a semi-insulating high resistance and an almost conductive low resistance by an electric signal or an optical signal, by incorporating it into an electric circuit, a very Control can be performed easily.

In particular, since the semiconductor layer does not have to be a single crystal, it can be formed directly on any substrate, and can be easily incorporated directly into a high-frequency circuit using a strip line or a waveguide. Circuit control can be performed very easily, and high-frequency circuit elements such as phase shifters and distributors, and high-frequency applied products such as phased array antennas using them can be easily obtained.

Further, since the on / off of the microwave can be controlled at high speed by the optical signal, a high-performance optical / microwave conversion circuit can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory view showing a manufacturing process of one embodiment of a semiconductor control circuit element according to the present invention.

FIG. 2 is an explanatory sectional view of an example in which a control circuit element in FIG. 1 is controlled by irradiation of light.

FIG. 3 is an explanatory diagram of an example of strip line control using the control circuit element of the present invention.

FIG. 4 is an explanatory diagram of an example in which a branch circuit is configured by strip lines.

FIG. 5 is an explanatory diagram of an example in which a phase shifter is configured by a strip line.

FIG. 6 is an explanatory diagram of an example in which a variable resistor is configured by a strip line.

FIG. 7 is an explanatory diagram of an example of controlling a coplanar circuit using the control circuit element of the present invention.

FIG. 8 is an explanatory diagram of an example in which a variable capacitor is configured using the control circuit element of the present invention.

FIG. 9 is an explanatory diagram of an example in which a variable inductor is configured using the control circuit element of the present invention.

FIG. 10 is an explanatory diagram of an example in which a switch circuit is configured using the control circuit element of the present invention.

FIG. 11 is an explanatory diagram of an example in which a waveguide whose transmission can be controlled is configured.

FIG. 12 is a diagram showing a change in resistance value of a semiconductor layer when n-type and P-type Si are doped with Au.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor control circuit element 2 Semiconductor layer 3 Heavy metal (Au) 5 Electrode 6 Electrode 10 Optical fiber

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/822 H01L 27/04 V H01P 11/00 RCLM (72) Inventor Manabu Arai Saitama 2-1-1 Fukuoka, Fukuoka City, New Japan Radio Co., Ltd. Kawagoe Works (72) Inventor, Futoshi Kuroki 6-8, Tsunouchi-cho, Kure-shi, Hiroshima F-term (reference) 2H037 AA04 BA02 DA04 DA06 5E030 AA20 5F038 AC01 AC05 AR11 AV01 AZ01 AZ04 CD20 DF02 EZ02 EZ14 EZ20 5F088 AA20 AB03 AB07 BA02 CB09 FA09

Claims (19)

[Claims] 1. A semiconductor layer doped with an n-type or p-type impurity, and at least a portion of the semiconductor layer is doped, and the n-type or p-type impurity in the doped portion is offset to increase the resistance. A light having a wavelength shorter than the wavelength that can excite the heavy metal, and longer than the wavelength that can excite the semiconductor layer, or the electric field is applied, whereby the heavy metal is excited,
A semiconductor control circuit element capable of reducing a resistance value of the semiconductor layer. 2. The n-type or p-type impurity to be doped.
Pure substance quantity is 1 × 10 ¹⁷~ 1 × 10¹⁴cm^-3And said
The heavy metal to be doped is substantially different from the n-type or p-type impurity.
2. The semiconductor control circuit element according to claim 1, wherein the amounts are substantially equal. 3. The semiconductor layer is made of an elemental semiconductor,
At least one of the heavy metals selected from the group consisting of gold and platinum;
3. The semiconductor control circuit element according to claim 1, wherein said element is a kind of metal. 4. The semiconductor control circuit device according to claim 1, wherein the semiconductor layer is made of a compound semiconductor or an alloy semiconductor, and the heavy metal is at least one metal selected from iron group metals. 5. The semiconductor control circuit according to claim 1, wherein a conductor layer, an insulator layer, or a composite layer thereof is provided with good adhesion on at least one surface side of said semiconductor layer. element. 6. The conductor layer, the insulator layer, or a composite layer thereof, which is made of a material having at least a transmittance for a wavelength of light capable of exciting the heavy metal.
13. The semiconductor control circuit element according to claim 1. 7. The semiconductor control circuit element according to claim 1, wherein the doping of the heavy metal is performed only near the surface of the semiconductor layer, and the semiconductor layer not doped with the heavy metal can be used as a conductor layer. 8. One end of an optical waveguide to which a light emitting source can be connected on the other end side is abutted against the surface of the semiconductor layer, or is inserted into the semiconductor layer, or
The semiconductor control circuit device according to claim 1, wherein the light can be irradiated by providing a light emitting device via a conductor layer or an insulator layer on a surface of the semiconductor layer. 9. The optical waveguide comprises a planar optical waveguide or an optical fiber, and a refractive index of light by a filler in the optical waveguide has a constant distribution in a direction perpendicular to a traveling direction of the light. 9. The semiconductor control circuit element according to claim 8, wherein 10. The semiconductor control device according to claim 1, wherein a conductor is provided on both upper and lower surfaces of the semiconductor layer, and the electric field can be applied by using the conductor as both electrodes. Circuit element. 11. The semiconductor control circuit element according to claim 1, wherein the semiconductor control circuit element has a wavelength longer than a wavelength of exciting the heavy metal and handles an electromagnetic wave including a direct current. An electrical circuit inserted to be affected by changes in 12. An electric network or a control network is formed on the semiconductor control circuit element directly or via an insulating film or on an insulating substrate on which the semiconductor control circuit element is formed. The electric circuit according to claim 11, wherein an element can be controlled by irradiating the light or applying an electric field. 13. An electric circuit for handling electromagnetic waves according to claim 11, wherein the electric circuit is an MIC, a coplanar circuit, an NRD guide, a coaxial line,
A high-frequency circuit having a high-frequency circuit element including at least one of a lumped constant circuit and a resonator. 14. The high-frequency circuit according to claim 13, wherein an electrode for applying an electric field for exciting a heavy metal of the semiconductor control circuit element is coupled to the high-frequency circuit element via a choke structure. 15. One side of the semiconductor control circuit element,
A transmission line having a branch portion is formed, and on / off of the line of the branch portion is controlled by the semiconductor control circuit element, so that at least one of a circuit switch, a phase shifter, a variable resistor, and a resonator is provided. 2. One is formed.
2. The electric circuit according to 1. 16. A location where the light for controlling the on / off is irradiated or an electric field is applied is λ / 4 (λ is a wavelength of an electromagnetic wave transmitted through the transmission line) from the branch point.
16. The electric circuit according to claim 15, wherein the electric circuit is provided at a position of an odd multiple of. 17. An electromagnetic wave transmission path is formed by providing a conductor along at least upper and lower surfaces of the semiconductor control circuit element according to claim 1, and the semiconductor control circuit element is inserted in the middle of the transmission path. Waveguide. 18. A circuit element is formed by providing a conductive film on at least one surface side of the semiconductor control circuit element according to claim 1, wherein the semiconductor element is formed by irradiating light or applying an electric field to the semiconductor control circuit element. Electric circuit element whose characteristics can be changed. 19. A microwave transmission line, and a semiconductor control circuit element capable of irradiating light according to claim 1 connected in the middle of said microwave transmission line, and capable of converting an optical signal into a microwave signal. Optical microwave conversion circuit.