Electronic element and circuit device

Abstract

To provide an electronic element and a circuit device.SOLUTION: An electronic element 100 includes a switch unit 10 that forms a field effect transistor, and an element unit 20 that is electrically connected to the switch unit 10 and forms a capacitor (passive element). The switch unit 10 includes a source electrode 5, a drain electrode 6, a channel formation film 4 formed overlapping with at least a part of the source electrode 5 and a part of the drain electrode 6, a gate insulating film 3 formed overlapping with the channel formation film 4, and a gate electrode 2 formed overlapping with the gate insulating film 3. The element unit 20 includes a terminal electrode 5a (first terminal electrode) electrically connected to the source electrode 5, and a terminal electrode 22 (second terminal electrode) that forms a capacitor (passive element) with the drain electrode 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electronic element that switches between the presence and absence of a physical quantity of a passive element, and a circuit device including the electronic element. [Background technology]

[0002] In order to realize an ideal AC rectifier, an electronic element capable of switching between a state with capacitance (capacitor) and a state without capacitance is required. However, as an electronic element, for example, a variable capacitance element capable of varying capacitance (capacitor) is known. Specifically, Patent Document 1 discloses a variable capacitance element in which a plate-shaped movable comb electrode and a plate-shaped fixed comb electrode are provided by using micromachining technology so as to face the movable comb electrode with a minute gap therebetween. In addition, Non-Patent Document 1 discloses a variable capacitance element with a two-terminal structure utilizing the ON / OFF operation of a FET (Field Effect Transistor). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-373829 A [Non-patent literature]

[0004] [Non-Patent Document 1] Tokumitsu Eisuke, Kikuchi Kazuya, "Evaluation of Channel Modulation in In2O3 / (Bi,La)4Ti3O12Ferroelectric-Gate Thin Film Transistors by Capacitance-Voltage Measurements", Ferroelectrics, 429, p.15-21, Jun 2012 Summary of the Invention [Problem to be solved by the invention]

[0005] The variable capacitance element disclosed in Patent Document 1 is configured to vary the capacitance by changing the distance between opposing comb-tooth electrodes. Therefore, in this variable capacitance element, there is a limit to the distance that can be changed, and in principle the capacitance cannot be made 0 (zero), and it is not possible to switch between a state with capacitance and a state without capacitance.

[0006] Moreover, the variable capacitance element disclosed in Non-Patent Document 1 is configured to vary the capacitance between the source electrode and the gate electrode by polarizing the gate insulating film (dielectric) by a voltage applied to the gate electrode. Therefore, in this variable capacitance element, the capacitance cannot be made 0 (zero) in principle by merely changing the electrode area on the source electrode side in a pseudo manner, and it is not possible to switch between a state with capacitance and a state without capacitance.

[0007] Therefore, an object of the present invention is to provide an electronic element and a circuit device that are capable of switching between a state in which a physical quantity (for example, capacitance) of a passive element is present and a state in which the physical quantity is absent. [Means for solving the problem]

[0008] An electronic element according to one embodiment of the present disclosure includes a switch section constituting a field effect transistor, and an element section electrically connected to the switch section and constituting a passive element, the switch section having a source electrode, a drain electrode, a channel formation film formed overlapping at least a portion of the source electrode and a portion of the drain electrode, a gate insulating film formed overlapping the channel formation film, and a gate electrode formed overlapping the gate insulating film, and the element section has a first terminal electrode electrically connected to the source electrode, and a second terminal electrode constituting a passive element between the switch section and the drain electrode.

[0009] A circuit device according to an embodiment of the present disclosure includes a circuit wiring and the above-described electronic element electrically connected to the circuit wiring. Effect of the Invention

[0010] According to the present disclosure, the element portion has a first terminal electrode electrically connected to the source electrode, and a second terminal electrode that constitutes a passive element between the first terminal electrode and the drain electrode, making it possible to switch between a state in which the physical quantity of the passive element is present and a state in which the physical quantity is not present. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view illustrating a configuration of an electronic device according to a first embodiment. [Diagram 2] FIG. 1 is a plan view illustrating a configuration of an electronic device according to a first embodiment. [Diagram 3] 1A to 1C are cross-sectional views illustrating a method for manufacturing an electronic device according to a first embodiment. [Figure 4] 1 is a circuit diagram of a multi-valued electronic element according to a first embodiment. [Diagram 5] FIG. 11 is a cross-sectional view illustrating a configuration of an electronic device according to a modified example of the first embodiment. [Figure 6] FIG. 11 is a cross-sectional view illustrating a configuration of an electronic device according to another modified example of the first embodiment. [Figure 7] FIG. 11 is a cross-sectional view illustrating the configuration of an electronic device according to a second embodiment. [Figure 8] FIG. 11 is a cross-sectional view illustrating the configuration of an electronic device according to a third embodiment. [Figure 9] FIG. 11 is a plan view for explaining the configuration of an electronic device according to a third embodiment. [Figure 10] 13 is a cross-sectional view for explaining a configuration of an electronic element according to a modified example. FIG. [Figure 11] 1 is a diagram for explaining the relationship between the capacitance and the holding voltage of an electronic element. [Figure 12] 1 is a diagram for explaining the relationship between the capacitance and retention time of an electronic element. [Figure 13] FIG. 11 is a cross-sectional view illustrating a configuration of an electronic element according to another modified example. [Figure 14] 4 is a diagram for explaining the relationship between the capacitance of an electronic element and the parasitic capacitance when a switch section is in an OFF state. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An electronic device according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. The electronic device described in the present disclosure is an element that can switch between a state in which a passive element has a physical quantity and a state in which the physical quantity does not exist, and the passive elements included therein include capacitors, inductors, resistors, etc. Note that the same reference numerals in the drawings indicate the same or equivalent parts. Furthermore, the state in which the physical quantity does not exist is not limited to a case in which the physical quantity is completely 0 (zero), but may be any physical quantity that is equal to or less than a predetermined quantity (for example, 1 / 10,000 or less) at which the physical quantity can be regarded as 0 (zero) in relation to a state in which the physical quantity exists.

[0013] (Embodiment 1) In the first embodiment, an electronic element including a capacitor as a passive element that can be switched between a state with capacitance and a state without capacitance will be described with reference to the drawings. Fig. 1 is a cross-sectional view for explaining the configuration of the electronic element 100 according to the first embodiment. Fig. 2 is a plan view for explaining the configuration of the electronic element 100 according to the first embodiment.

[0014] 1 includes a switch section 10 constituting a field effect transistor formed on a semiconductor substrate 1, and an element section 20 constituting a passive element and electrically connected to the switch section 10. The element section 20 is provided on the upper part of the switch section 10.

[0015] The switch section 10 has a gate electrode 2, a gate insulating film 3, a channel forming film 4, a source electrode 5, and a drain electrode 6. In the switch section 10 shown in Fig. 1, the gate electrode 2 is formed on a semiconductor substrate 1, the gate insulating film 3 and the channel forming film 4 are formed in this order on the gate electrode 2, and the source electrode 5 and the drain electrode 6 are formed thereon, respectively.

[0016] More specifically, the switch section 10 is an oxide FET (Field Effect Transistor). For example, lanthanum aluminate (LAO) is used for the semiconductor substrate 1, and a gate electrode 2 is formed thereon with platinum (Pt) in a predetermined pattern as shown in FIG. 2. For example, a La-HfO2 film with a thickness of 70 nm is used for the gate insulating film 3, and an IZO film with a thickness of 25 nm is used for the channel forming film 4. On the channel forming film 4 of the IZO film, a source electrode 5 and a drain electrode 6 are formed with platinum (Pt) in a predetermined pattern as shown in FIG. 2. Note that a terminal electrode 5a (first terminal electrode) is provided on the source electrode 5 shown in FIG. 2, but the source electrode 5 itself may be used as the terminal electrode 5a. For example, the channel width W of the switch section 10 is 100 μm and the channel length L is 10 μm.

[0017] The element section 20 is provided only on the drain electrode 6, and includes an Al2O3 film of a dielectric 21, and a platinum (Pt) terminal electrode 22 (second terminal electrode) formed on the dielectric 21. The terminal electrode 22 is formed in a predetermined pattern as shown in Fig. 2. The gate electrode 2 is drawn out from the region where the source electrode 5 and drain electrode 6 overlap, as shown in Fig. 2, and a control electrode terminal 2a is provided on the gate electrode 2.

[0018] The element unit 20 does not constitute a capacitor (passive element) because no dielectric 21 is provided between the source electrode 5 and the terminal electrode 22. On the other hand, the element unit 20 constitutes a capacitor (passive element) because the dielectric 21 is provided between the drain electrode 6 and the terminal electrode 22. The capacitor is a portion C1 where the drain electrode 6 including the channel formation film 4 and the terminal electrode 22 overlap in a plan view.

[0019] When the switch unit 10 of the electronic element 100 is in the OFF state, a gate voltage equal to or higher than the threshold value is not applied to the gate electrode 2, so that an electron depletion layer is formed at the position of the channel formation film 4 that overlaps with the gate electrode 2 in a planar view, and there is no electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100, a voltage is applied only to the source electrode 5, and the source electrode 5 that has no portion overlapping with the terminal electrode 22 in a planar view does not constitute a capacitor.

[0020] However, when the switch section 10 of the electronic element 100 is in the ON state, a channel is formed by applying a gate voltage equal to or higher than a threshold value to the gate electrode 2, thereby establishing electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100, a voltage is applied to the source electrode 5 and the drain electrode 6 (including the channel-forming film 4 therebetween), and a capacitor is formed between the terminal electrode 22 and the drain electrode 6, which overlap in a planar view.

[0021] That is, in the electronic element 100, the capacitor is turned ON / OFF by switching between a state in which there is no capacitor and a state in which there is a capacitor by turning the switch section 10 ON / OFF. The electronic element 100 is an electronic element that operates with three terminals, being separated into the switch section 10 that performs ON / OFF operation by a voltage applied to the gate electrode 2 (control electrode terminal 2a) and the element section 20 that operates with the terminal electrode 5a (first terminal electrode) and the terminal electrode 22 (second terminal electrode).

[0022] In the switch section 10, it is desirable to make the gate insulating film 3 thin from the viewpoint of power consumption, and although making the film thinner reduces the withstand voltage, it also reduces the driving voltage, making it possible to drive at a low voltage. Therefore, in the electronic device 100, by utilizing the structure in which the gate electrode 2 and the device section 20 of the switch section 10 are electrically separated, the film thickness of the gate insulating film 3 is made thin to achieve low-voltage driving and low withstand voltage, and the dielectric 21 can be made thick and have a laminated structure to increase the capacity, thereby making it possible to achieve both high withstand voltage and high capacity.

[0023] In addition, in the electronic element 100, the gate electrode 2 (control electrode terminal 2a) of the switch section 10 is electrically separated from the terminal electrode 5a (first terminal electrode) and the terminal electrode 22 (second terminal electrode) of the element section 20, so that the operation of the switch section 10 is not affected by a signal on the element section 20 side. The terminal electrode 5a (first terminal electrode) and the terminal 22a of the terminal electrode 22 (second terminal electrode) of the electronic element 100 are connected to a filter circuit or the like, while the control electrode terminal 2a for switching between the presence and absence of capacitance is connected to a circuit other than the filter circuit. Therefore, there is a low possibility that the signal applied to the control electrode terminal 2a will be affected by the signal of the filter circuit.

[0024] Furthermore, in the electronic device 100, the electrical resistance of the channel formation film 4 between the source electrode 5 and the drain electrode 6 can be reduced by shortening the channel length L of the switch section 10. Therefore, in the electronic device 100, in order to quickly switch between the presence and absence of capacitance, it is possible to address this by improving the switching speed (time constant) of the switch section 10.

[0025] Next, a method for manufacturing the electronic device 100 will be described with reference to the drawings. Fig. 3 is a cross-sectional view for explaining a method for manufacturing the electronic device according to the first embodiment. First, in Fig. 3(a), a gate electrode 2 made of platinum (Pt) and having a thickness of 80 nm is formed on the (100) surface of a prepared semiconductor substrate 1 made of lanthanum aluminate (LAO). Specifically, the gate electrode 2 is formed by forming a photoresist of a predetermined pattern on the (100) surface of the semiconductor substrate 1 using a photolithography technique, then depositing a platinum (Pt) film by radio frequency (RF) sputtering, and removing the photoresist by lift-off.

[0026] 3(b), a gate insulating film 3 with a thickness of 70 nm is formed on the surface of the semiconductor substrate 1 on which the gate electrode 2 is formed. Specifically, the gate insulating film 3 is formed by spin-coating a La-HfO2 solution onto the surface of the semiconductor substrate 1 on which the gate electrode 2 is formed using a chemical solution deposition (CSD) method, drying the film at 150°C, and then baking the film at 800°C in an oxygen atmosphere to crystallize the film.

[0027] In Fig. 3(c), a channel formation film 4 with a thickness of 25 nm is formed on the gate insulating film 3. Specifically, the channel formation film 4 is formed by using chemical solution deposition (CSD) to spin-coat an IZO solution on the gate insulating film 3, drying it at 150°C, and then baking it at 500°C in an oxygen atmosphere to crystallize it.

[0028] 3(d), a source electrode 5 and a drain electrode 6 made of platinum (Pt) with a thickness of 80 nm are formed on the channel formation film 4. Specifically, the source electrode 5 and the drain electrode 6 are formed by forming a photoresist of a predetermined pattern on the channel formation film 4 using a photolithography technique, then depositing platinum (Pt) by radio frequency (RF) sputtering, and removing the photoresist by lift-off.

[0029] In Fig. 3(e), the dielectric 21 is a 500 nm-thick Al2O3 film only on the drain electrode 6. Specifically, the dielectric 21 is formed by forming a photoresist of a predetermined pattern on the drain electrode 6 using photolithography technology, then depositing an Al2O3 film by ECR (Electron Cyclotron Resonance) sputtering, and removing the photoresist by lift-off.

[0030] 3(f), a terminal electrode 22 made of platinum (Pt) and having a thickness of 80 nm is formed on the dielectric 21. Specifically, the terminal electrode 22 is formed by forming a photoresist of a predetermined pattern on the dielectric 21 using a photolithography technique, then depositing platinum (Pt) by radio frequency (RF) sputtering, and removing the photoresist by lift-off.

[0031] The electronic element 100 described so far is an element that can be switched between a state in which there is no capacitor and a state in which there is a capacitor. However, by forming a plurality of electronic elements 100 in a matrix on a semiconductor substrate 1, a multi-valued electronic element can be configured. FIG. 4 is a circuit diagram of a multi-valued electronic element 100a according to the first embodiment. Note that a similar multi-valued electronic element can be configured by forming a plurality of electronic elements, such as inductors and resistors, other than capacitors as passive elements in a matrix.

[0032] 4 shows a circuit diagram of an electronic element 100a in which n×n electronic elements 100 shown in FIG. 1 are connected in a matrix. In the electronic element 100a shown in FIG. 4, the terminal electrode 5a (first terminal electrode) and the terminal electrode 22 (second terminal electrode) are common to the n×n electronic elements 100. However, the control electrode terminals 2a of the n×n electronic elements 100 are provided separately, and are shown in FIG. 4 as terminals G11 to Gnn. By supplying signals to these terminals G11 to Gnn, a required number of electronic elements 100 can be turned on to obtain a required capacitance, and therefore the electronic element 100a can have a multi-valued capacitance.

[0033] In the electronic element 100, the dielectric 21 of the element part 20 is provided only on the drain electrode 6 as shown in FIG. 1, but the dielectric may also be provided on a part of the source electrode 5 and on the channel forming film 4 between the source electrode 5 and the drain electrode 6. Specifically, an electronic element in which the dielectric is provided on a part of the source electrode 5 and on the channel forming film 4 between the source electrode 5 and the drain electrode 6 will be described. FIG. 5 is a cross-sectional view for explaining the configuration of an electronic element 100b according to a modification of the first embodiment. In the electronic element 100b shown in FIG. 5, the same components as those of the electronic element 100 shown in FIG. 1 are denoted by the same reference numerals and detailed description will not be repeated.

[0034] 5 includes a switch section 10 constituting a field effect transistor formed on a semiconductor substrate 1, and an element section 20b constituting a passive element and electrically connected to the switch section 10. The element section 20b is provided on the upper part of the switch section 10.

[0035] The element section 20b includes an Al2O3 film of a dielectric 21b provided on an upper portion extending from a part of the source electrode 5 to the drain electrode 6, and a platinum (Pt) terminal electrode 22 (second terminal electrode) formed on the upper portion of the dielectric 21b and overlapping with the drain electrode 6 in a planar view. Although the terminal electrode 22 overlaps only with the drain electrode 6 in a planar view, it may be provided on an upper portion of the channel forming film 4 between the source electrode 5 and the drain electrode 6 as long as it does not overlap with the source electrode 5.

[0036] The dielectric 21b can protect a part of the source electrode 5 and an upper part of the channel formation film 4 between the source electrode 5 and the drain electrode 6 by covering these parts. The terminal electrode 22 is provided only at a position overlapping with the drain electrode 6 in a planar view, similar to the electronic element 100 shown in FIG. 1, and therefore does not form a capacitor (passive element) between the source electrode 5 and the terminal electrode 22.

[0037] In the electronic element 100b, the dielectric 21b is present in the portion connecting the end of the source electrode 5 and the end of the terminal electrode 22, so that the portion may have a capacitance. However, since the source electrode 5 and the terminal electrode 22 do not overlap in a plan view, the capacitance formed in the portion is extremely small.

[0038] Furthermore, in the electronic device 100, a configuration in which the element section 20 is provided above the switch section 10 as shown in Fig. 1 has been described, but the element section 20 may be provided below the switch section 10. Specifically, an electronic device in which the element section 20 is provided below the switch section 10 will be described. Fig. 6 is a cross-sectional view for illustrating the configuration of electronic devices 100c, 100d according to another modified example of the first embodiment. Note that in the electronic devices 100c, 100d shown in Fig. 6, the same components as those in the electronic device 100 shown in Fig. 1 are denoted by the same reference numerals and detailed description will not be repeated.

[0039] 6(a) shows an electronic element 100c using a multi-layer ceramic capacitor (MLCC) in the element section 20c. In the electronic element 100c, a source electrode 5 and a drain electrode 6 are formed on the upper surface of the multi-layer ceramic capacitor of the element section 20c, and a channel formation film 4, a gate insulating film 3, and a gate electrode 2 are formed thereon in this order to constitute a switch section 10.

[0040] The multilayer ceramic capacitor of the element section 20c includes a capacitor portion connected to the drain electrode 6. The capacitor portion is configured by laminating a plurality of electrodes, each of which includes an electrode 23c connected to the drain electrode 6 and an electrode 24c connected to a terminal electrode 22c that is an external electrode of the multilayer ceramic capacitor, with a dielectric 21c of, for example, barium titanate sandwiched therebetween.

[0041] In the electronic element 100c, similarly to the electronic element 100, when the switch unit 10 is in the OFF state, a gate voltage equal to or higher than the threshold value is not applied to the gate electrode 2, so that an electron depletion layer is formed at the position of the channel formation film 4 that overlaps with the gate electrode 2 in a planar view, and there is no electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100c, a voltage is applied only to the source electrode 5, and the source electrode 5 that does not have a terminal electrode 22c in an opposing portion does not constitute a capacitor.

[0042] On the other hand, in the electronic element 100c, when the switch unit 10 is in the ON state, a channel is formed by applying a gate voltage equal to or higher than the threshold value to the gate electrode 2, thereby establishing electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100c, a voltage is applied to the dielectric 21c between the electrode 23c connected to the drain electrode 6 and the electrode 24c connected to the opposing terminal electrode 22c, so that a capacitor is formed.

[0043] Various configurations such as low temperature co-fired ceramics (LTCC) and high temperature co-fired ceramics (HTCC) can be applied to the multilayer ceramic capacitor portion of the element section 20c.

[0044] 6(b) shows an electronic element 100d using a silicon capacitor in the element section 20d. In the electronic element 100d, a source electrode 5 and a drain electrode 6 are formed on the upper surface of the silicon capacitor of the element section 20d, and a channel formation film 4, a gate insulating film 3, and a gate electrode 2 are formed thereon in this order to constitute a switch section 10.

[0045] The silicon capacitor of the element section 20d is formed by a semiconductor process, and is composed of an N+ layer 24d formed by implanting n-type impurity ions into the silicon substrate 1a, a dielectric 21d formed on the surface of the N+ layer 24d, and a polysilicon layer 23d formed on the surface of the dielectric 21d and connected to the drain electrode 6. The dielectric 21d is made of an inorganic material such as silicon oxide, silicon nitride, hafnium oxide, hafnium silicate, alumina, barium titanate, etc., formed by a CVD (Chemical Vapor Deposition) method, for example. Note that a plurality of trenches or a plurality of pillars are formed in the silicon substrate 1a to form an uneven shape.

[0046] The silicon capacitor of the element portion 20d includes a capacitor portion connected to the drain electrode 6. The capacitor portion is composed of a portion of the dielectric 21d sandwiched between the polysilicon layer 23d connected to the drain electrode 6 and the N+ layer 24d connected to the terminal electrode 22d.

[0047] In the electronic element 100d, similarly to the electronic element 100, when the switch unit 10 is in the OFF state, a gate voltage equal to or higher than the threshold value is not applied to the gate electrode 2, so that an electron depletion layer is formed at the position of the channel formation film 4 that overlaps with the gate electrode 2 in a planar view, and there is no electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100d, a voltage is applied only to the source electrode 5, and the source electrode 5 that does not have a terminal electrode 22d in an opposing portion does not constitute a capacitor.

[0048] On the other hand, in the electronic element 100d, when the switch unit 10 is in the ON state, a channel is formed by applying a gate voltage equal to or higher than the threshold value to the gate electrode 2, thereby establishing electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 100d, a voltage is applied to a portion of the dielectric 21d sandwiched between the polysilicon layer 23d connected to the drain electrode 6 and the N+ layer 24d connected to the terminal electrode 22d, so that a capacitor is formed.

[0049] In the silicon capacitor of element portion 20d, the capacitance of element portion 20d is increased by providing an uneven portion on silicon substrate 1a, but dielectric 21d may be in the shape of a parallel plate as long as the necessary capacitance can be ensured.

[0050] As described above, the electronic device 100 according to the first embodiment includes the switch section 10 constituting a field effect transistor, and the element section 20 electrically connected to the switch section 10 and constituting a capacitor (passive element). The switch section 10 includes a source electrode 5, a drain electrode 6, a channel formation film 4 formed overlapping at least a part of the source electrode 5 and a part of the drain electrode 6, a gate insulating film 3 formed overlapping the channel formation film 4, and a gate electrode 2 formed overlapping the gate insulating film 3. The element section 20 includes a terminal electrode 5a (first terminal electrode) electrically connected to the source electrode 5, and a terminal electrode 22 (second terminal electrode) constituting a capacitor (passive element) between the switch section 10 and the drain electrode 6.

[0051] As a result, in the electronic device 100 according to the first embodiment, the device section 20 has a terminal electrode 5a (first terminal electrode) electrically connected to the source electrode 5, and a terminal electrode 22 (second terminal electrode) which does not form a capacitor (passive element) between itself and the source electrode 5, but forms a capacitor (passive element) at least between itself and the drain electrode 6, and by turning the switch section 10 on and off, it becomes possible to switch between a state with a capacitor (passive element) and a state without a capacitor (passive element). Note that the switch section 10 is preferably provided on the upper or lower part of the device section 20.

[0052] Preferably, the element portion 20 further includes a dielectric 21 provided so as to overlap at least the drain electrode 6, and the terminal electrode 22 overlaps the drain electrode 6 in a planar view, forming a capacitor together with the drain electrode 6 and the dielectric 21.

[0053] It is also preferable that the gate electrode 2 is formed on the semiconductor substrate 1, the gate insulating film 3 is formed on the gate electrode 2 and the semiconductor substrate 1, the channel formation film 4 is formed on the gate insulating film 3, the source electrode 5 and the drain electrode 6 are formed on the channel formation film 4, the dielectric 21 is formed only on the drain electrode 6, and the terminal electrode 22 is formed only on the dielectric 21.

[0054] The electronic elements 100, 100a to 100d have a certain capacitance when the switch section 10 is in the ON state, and the capacitance becomes 0 (zero) when the switch section 10 is in the OFF state, so that they can be used as an ideal AC rectifier (switched capacitor). Here, the impedance Z of the switched capacitor is expressed as Z=1 / (jωC). By using the electronic elements 100, 100a to 100d in the switched capacitor, this impedance Z can modulate C (capacitor) instead of changing the clock frequency. Therefore, in the switched capacitor using the electronic elements 100, 100a to 100d, the noise factor due to the high frequency clock can be eliminated. Also, in the switched capacitor using the electronic elements 100, 100a to 100d, when the switch section 10 is in the OFF state, the capacitance becomes 0 (zero) and the impedance Z becomes infinite. Furthermore, by electrically connecting the electronic elements 100, 100a to 100d to circuit wiring, they can be applied to small, low-loss phase shifters, impedance matching circuits (antenna systems), and various filter circuits (CR circuits, LC circuits, active filter circuits, and the like).

[0055] (Embodiment 2) The electronic device according to the first embodiment has been described as an electronic device in which the passive element included is a capacitor and can be switched between a state with capacitance and a state without capacitance, but the passive element included is not limited to a capacitor. The electronic device according to the second embodiment will be described with reference to the drawings as an electronic device in which the passive element included is an inductor and can be switched between a state with inductance and a state without inductance. FIG. 7 is a cross-sectional view for explaining the configuration of the electronic device 200 according to the second embodiment. In the electronic device 200 shown in FIG. 7, the same components as those in the electronic devices shown in FIG. 1 and FIG. 6 are denoted by the same reference numerals and detailed description will not be repeated.

[0056] 7 includes a switch section 10 constituting a field effect transistor, and an element section 20A constituting a passive element and electrically connected to the switch section 10. The element section 20A is provided below the switch section 10.

[0057] The switch section 10 has a gate electrode 2, a gate insulating film 3, a channel forming film 4, a source electrode 5, and a drain electrode 6. In the switch section 10 shown in Fig. 7, the source electrode 5 and the drain electrode 6 are formed on the upper surface of the element section 20A, and the channel forming film 4, the gate insulating film 3, and the gate electrode 2 are formed thereon in this order to constitute the switch section 10.

[0058] As shown in FIG. 7, in the electronic element 200, the element part 20A is an inductor, and includes an inductor portion connected to the drain electrode 6. The inductor portion is composed of a coil electrode 24 connected to the drain electrode 6 and a terminal electrode 22A which is an external electrode of the inductor. The coil electrode 24 is formed in a nonmagnetic ceramic 25. Although a terminal electrode 5a (first terminal electrode) is provided on the source electrode 5 shown in FIG. 7, the source electrode 5 itself may be used as the terminal electrode 5a. Furthermore, a control electrode terminal 2a is provided on the gate electrode 2 shown in FIG. 7, but the gate electrode 2 itself may be used as the control electrode terminal 2a. Furthermore, a terminal 22a of the terminal electrode 22A is provided on the terminal electrode 22A shown in FIG. 7, but the terminal electrode 22A itself may be used as the terminal 22a.

[0059] In the electronic element 200, similarly to the electronic element 100, when the switch unit 10 is in the OFF state, a gate voltage equal to or higher than the threshold is not applied to the gate electrode 2, so that an electron depletion layer is formed at the position of the channel formation film 4 that overlaps with the gate electrode 2 in a planar view, and there is no electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 200, a voltage is applied only to the source electrode 5, and there is no coil electrode between the source electrode 5 and the terminal electrode 22A, so that no inductance is formed.

[0060] On the other hand, when the switch unit 10 of the electronic element 200 is in the ON state, a channel is formed by applying a gate voltage equal to or higher than the threshold value to the gate electrode 2, thereby establishing electrical continuity between the source electrode 5 and the drain electrode 6. Therefore, in the electronic element 200, a current flows through the coil electrode 24 between the drain electrode 6 and the terminal electrode 22A, forming an inductance.

[0061] In the electronic element 200, the terminal electrode 5a (first terminal electrode) and the terminal 22a of the terminal electrode 22A (second terminal electrode) are connected to a filter circuit or the like, while the control electrode terminal 2a for switching between the presence and absence of inductance is connected to a circuit other than the filter circuit. Therefore, there is a low possibility that the signal applied to the control electrode terminal 2a will be affected by the signal of the filter circuit.

[0062] As described above, in the electronic element 200 according to the second embodiment, the passive element is an inductor, and the element portion 20A has the coil electrode 24 electrically connected between the drain electrode 6 and the terminal electrode 22A.

[0063] As a result, the electronic element 200 according to the second embodiment forms an inductor between the drain electrode 6 and the terminal electrode 22A, and is therefore capable of switching between a state with inductance and a state without inductance.

[0064] A multi-valued electronic element may be configured by forming a plurality of electronic elements 200 in a matrix. Also, by changing the coil electrode 24 shown in Fig. 7 to a resistive element, an electronic element may be configured with a resistor as a passive element. Furthermore, the configuration of the switch section 10 described in the first and second embodiments is not limited to the described configuration, and may be, for example, a silicon MOSFET or a GaN FET.

[0065] By electrically connecting the electronic element 200 to circuit wiring, it can be applied to a small, low-loss phase shifter, an impedance matching circuit (antenna system), or various filter circuits (CR circuits, LC circuits, active filter circuits, etc.).

[0066] (Embodiment 3) In the first embodiment, it has been described that the switch section 10 has the gate electrode 2, the gate insulating film 3, the channel formation film 4, the source electrode 5, and the drain electrode 6. Of these, the drain electrode 6 is a floating electrode, and it is possible to configure a switch section without the drain electrode 6. In the electronic element according to the third embodiment, a configuration in which the drain electrode, which is a floating electrode, is not provided will be described with reference to the drawings. FIG. 8 is a cross-sectional view for explaining the configuration of the electronic element 100e according to the third embodiment. FIG. 9 is a plan view for explaining the configuration of the electronic element 100e according to the third embodiment. In the electronic element 100e shown in FIGS. 8 and 9, the same components as those in the electronic element 100 shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description will not be repeated.

[0067] 8 includes a switch section 10e constituting a field effect transistor formed on a semiconductor substrate 1, and an element section 20 constituting a passive element and electrically connected to the switch section 10e. The element section 20 is provided on the upper part of the switch section 10e.

[0068] The switch section 10e has a gate electrode 2e, a gate insulating film 3, a channel formation film 4, and a source electrode 5. In the switch section 10e shown in Fig. 8, the gate electrode 2e is formed on the semiconductor substrate 1, the gate insulating film 3 and the channel formation film 4 are formed in this order on the gate electrode 2e, and the source electrode 5 is formed thereon.

[0069] In the switch section 10e, a drain electrode is not provided, but instead the gate electrode 2e is expanded as shown in Fig. 9, so that most of the terminal electrode 22 overlaps with the gate electrode 2e in a planar view. Therefore, when the switch section 10e is turned on, a gate voltage is applied to the gate electrode 2e in the electronic element 100e, and a channel charge is generated in a portion of the channel formation film 4 that overlaps with the gate electrode 2e in a planar view. In the electronic element 100e, a voltage is applied between the portion of the channel formation film 4 and the terminal electrode 22 facing that portion, so that a capacitance is formed.

[0070] On the other hand, when the switch unit 10e is in the OFF state, in the electronic element 100e, a gate voltage is not applied to the gate electrode 2e, and therefore a channel charge is not generated in the channel formation film 4. Therefore, in the electronic element 100e, a voltage is applied only to the source electrode 5, and the source electrode 5, which has no portion overlapping with the terminal electrode 22 in a plan view, does not constitute a capacitor.

[0071] The element section 20 forms a capacitor (passive element) between the gate electrode 2e and the terminal electrode 22. Specifically, the capacitor is a portion C2 where the gate electrode 2e and the terminal electrode 22 overlap in a plan view.

[0072] Even in the electronic element 100e, by turning on / off the switch section 10e, it is possible to switch between a state in which there is no capacitor and a state in which there is a capacitor, thereby turning the capacitor on / off. Even in the electronic element 100e, it is an electronic element that operates with three terminals, being separated into the switch section 10e that performs on / off operation by a voltage applied to the gate electrode 2e (control electrode terminal 2a) and the element section 20 that operates with the terminal electrode 5a (first terminal electrode) and the terminal electrode 22 (second terminal electrode).

[0073] However, in the electronic element 100e, since the capacitance of the capacitor element is determined by the channel charge generated in the channel formation film 4 without providing a drain electrode, the capacitance of the capacitor element can be continuously varied by the voltage applied to the gate electrode 2e. Also, in the electronic element 100e, since the drain electrode, which is a floating electrode, is not provided, the residual charge in the floating electrode during ON / OFF operation of the switch section 10e is reduced, so that the potential of the capacitor can be stabilized and the risk of failure due to a short circuit can be reduced.

[0074] As described above, the electronic element 100e according to the third embodiment uses the portion C2 where the gate electrode 2e and the channel formation film 4 overlap in a planar view, instead of a drain electrode. A capacitor element is formed between the portion C2 and the terminal electrode 22. This allows the electronic element 100e to continuously vary the capacitance of the capacitor element.

[0075] In the electronic element 100e, the element section 20 is provided above the switch section 10e as shown in Fig. 8, but the element section 20 may be provided below the switch section 10e. Also, a multi-valued electronic element may be similarly configured by forming a plurality of electronic elements 100e in a matrix. Furthermore, the configuration of the electronic element 100e may be applied to electronic elements other than capacitors, such as inductors and resistors.

[0076] By electrically connecting the electronic device 100e to circuit wiring, it can be applied to a small, low-loss phase shifter, an impedance matching circuit (antenna system), or various filter circuits (CR circuits, LC circuits, active filter circuits, etc.).

[0077] (Modification) (1) In the electronic devices 100, 100a to 100e, and 200 described in the above embodiments, in order to improve the switching speed, that is, the Q value (Q=1 / ωCR) of the switch section 10 needs to be improved. Here, ω is each frequency. That is, the switching speed can be improved by reducing the parasitic resistance R and the capacitor C (parasitic capacitance).

[0078] The parasitic resistance R corresponds to the series resistance of the channel formation film 4 and is given by R=ρ(L / (Wt)), where ρ is the resistivity specific to the material of the channel formation film 4, L is the channel length, W is the channel width, and t is the film thickness of the channel formation film 4.

[0079] As described above, the parasitic resistance R depends on the value of channel length L / channel width W. Therefore, the Q value can be improved by increasing the channel width W relative to the channel length L. Since the switch section 10 has the source electrode 5 and the drain electrode 6 provided on the channel formation film 4 as shown in FIG. 2, the channel length L and the channel width W can be easily changed by device design.

[0080] On the other hand, the capacitor C (parasitic capacitance) corresponds to the capacitance of the gate insulating film 3 of the switch section 10, and is proportional to the relative dielectric constant and inversely proportional to the film thickness of the gate insulating film 3. Therefore, since the switch section 10 has a structure separated from the element section 20, it is possible to adjust the capacitor C (parasitic capacitance) separately.

[0081] For example, in the electronic device 100 described in the first embodiment, if the channel length L is 10 μm, the channel width W is 100 μm, the parasitic resistance R is 1 kΩ, and the capacitor C (parasitic capacitance) is 10 pF, the Q value is 0.02 at 1 MHz. Here, if the channel length L is miniaturized to 1 μm, the channel width W is 1000 μm, the thickness of the gate insulating film 3 is 10 times (7000 μm), and the relative dielectric constant of the gate insulating film 3 is 1 / 5 (about 40 to 50), the Q value becomes 100. Therefore, the switching speed of the switch section 10 can be improved by 5000 times.

[0082] (2) In the electronic element described in the above embodiment, the channel-forming film 4 is formed below the source electrode 5 and the drain electrode 6 as shown in FIG. 1 (top contact structure). The top contact structure is a structure in which the channel-forming film 4 contacts the source electrode 5 and the drain electrode 6 on the upper side as viewed from the gate electrode 2 side. However, the present invention is not limited to this, and the electronic element may have the channel-forming film 4 formed above the source electrode 5 and the drain electrode 6 (bottom contact structure). The bottom contact structure is a structure in which the channel-forming film 4 contacts the source electrode 5 and the drain electrode 6 on the lower side as viewed from the gate electrode 2 side.

[0083] In the electronic device 100 described in the above embodiment, as shown in FIG. 1, a bottom gate structure is adopted in which a gate electrode 2 is formed on a semiconductor substrate 1, a gate insulating film 3 and a channel forming film 4 are formed in sequence on the gate electrode 2, and a source electrode 5 and a drain electrode 6 are formed on the gate insulating film 3. However, the electronic device is not limited to this, and a top gate structure may be adopted. FIG. 10 is a cross-sectional view for explaining the configuration of an electronic device 100f according to a modified example. In the electronic device 100f, as shown in FIG. 10, the device section 20 is provided below the switch section 10. The switch section 10 adopts a top gate structure in which a source electrode 5 and a drain electrode 6 are formed on a dielectric 21, a channel forming film 4 and a gate insulating film 3 are formed in sequence on the source electrode 5 and the drain electrode 6, and a gate electrode 2 is formed on the gate insulating film 3. In the electronic device 100f shown in FIG. 10, the same components as those of the electronic device 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

[0084] 10, the electronic element 100f with the top gate structure employs a top contact structure in which the source electrode 5 and the drain electrode 6 are in contact with the upper side of the channel formation film 4 as viewed from the gate electrode 2 side. However, without being limited thereto, the electronic element 100f with the top gate structure may also employ a bottom contact structure in which the source electrode 5 and the drain electrode 6 are in contact with the lower side of the channel formation film 4 as viewed from the gate electrode 2 side.

[0085] (3) Below is a list of materials that can be used for the gate insulating film 3 and the dielectric 21. Of course, the materials are not limited to the following list. Amorphous or polycrystalline metal oxides such as SiO2, Al2O3, HfO2, ZrO2, La2O3, Ta2O5 ·Nitride films such as SiN, Si3N4, and SiON Ferroelectric HfO2, and ferroelectric films in which HfO2 is doped with at least one type of trivalent, tetravalent or pentavalent metal atom such as Si, Ce, Y, Zr, Bi, Ni, Ta or La, ferroelectric materials with PbTiO3 as the host crystal, ferroelectric materials with BaTiO3 as the host crystal, ferroelectric materials with Bi layer structure, other metal oxides with perovskite crystal, metal oxides with pyrochlore crystal, organic ferroelectric materials, other resin materials (polyimide, acrylic, epoxy, polypropylene, polyester, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polylactic acid, etc.) Below is a list of materials that can be used for the channel formation film 4. Of course, the materials are not limited to the following list. In-O, In-Sn-O, In-Zn-O, In-Sn-Zn-O, In-Ga-Zn-O, In-Ga-O, Ga-O, Zn-O, Al-Zn-O, Sn-O, Ti-O based n-type oxide semiconductors Cu-O, Sn-O, Zn-O based p-type oxide semiconductors Cu-Sn-I amorphous p-type oxide semiconductor ·Si semiconductors such as n-type Si, p-type Si, and SiC -Nitride semiconductors such as GaN Graphene, a two-dimensional conductive material based on transition metal chalcogenides ·Perovskite-type conductive materials such as LaNiO3, BaSnO3, SrTiO3 (4) In the electronic elements 100 to 100f described in the above embodiments, when a ferroelectric film such as a La-HfO2 film is used for the gate insulating film 3, the electronic elements 100 to 100f include the configuration of a ferroelectric gate transistor. Therefore, the electronic elements 100 to 100f have memory characteristics derived from the configuration of a ferroelectric gate transistor. Specifically, in the electronic element 100 shown in FIG. 1, when an ON voltage (e.g., +10 V) is applied to the gate electrode 2 to form a capacitor between the terminal electrode 22 and the drain electrode 6, the capacitance value C oncan be maintained by simply applying a holding voltage of 0 (zero) V or a small constant value (e.g., −1.0 V) to the gate electrode 2. Similarly, in the electronic element 100, the capacitance value C generated when an OFF voltage (e.g., −10 V) is applied to the gate electrode 2 and a capacitor is not formed between the terminal electrode 22 and the drain electrode 6 is off can be held at this state simply by applying a holding voltage of 0 (zero) V or a small constant value (eg, −1.0 V) to the gate electrode 2.

[0086] FIG. 11 is a diagram for explaining the relationship between the capacitance and the holding voltage of an electronic element. In FIG. 11, the horizontal axis is the gate voltage, and the vertical axis is the capacitance. When a ferroelectric gate transistor is configured using a ferroelectric film such as a La-HfO2 film as the gate insulating film 3, as shown in FIG. 11, the change in capacitance value C occurring between the terminal electrode 22 and the drain electrode 6 with respect to the gate voltage Vg applied to the gate electrode 2 forms a hysteresis curve. In FIG. 11, the capacitance value C on and capacitance value C off It is clear that it can be maintained.

[0087] 12 is a diagram for explaining the relationship between the capacitance and the retention time of an electronic element. In FIG. 12, the horizontal axis represents time, and the vertical axis represents capacitance. As shown in FIG. 12, with a retention voltage of −1.0 V applied to the gate electrode 2, 5 sec (27 hours), the capacitance value C on and capacitance value C off Therefore, when a ferroelectric gate transistor configuration is adopted in the electronic devices 100 to 100f, it is not necessary to apply a high gate voltage to maintain the capacitance, so that power can be saved and deterioration of the device can be suppressed.

[0088] (5) In the electronic elements 100 to 100f described in the above embodiments, when the gate electrode 2 is viewed in a plan view, the gate electrode 2 and the drain electrode 6 have an overlapping portion (see FIG. 1, FIG. 2, etc.). However, since the gate electrode 2 and the drain electrode 6 have an overlapping portion in a plan view, a parasitic capacitance C3g is generated in the overlapping portion. Therefore, in the electronic elements 100 to 100f, the parasitic capacitance C3g remains even when the switch unit is turned off. The parasitic capacitance C3g depends on the area of ​​the overlapping portion between the gate electrode 2 and the drain electrode 6 in a plan view.

[0089] Therefore, an electronic element that sets the parasitic capacitance C3g to approximately 0 (zero) will be described. Fig. 13 is a cross-sectional view for explaining the configuration of an electronic element 100g according to another modified example. In the electronic element 100g shown in Fig. 13, the same components as those in the electronic element 100 shown in Fig. 1 are denoted by the same reference numerals and detailed description will not be repeated.

[0090] 13 includes a switch section 10g constituting a field effect transistor formed on a semiconductor substrate 1, and an element section 20 constituting a passive element and electrically connected to the switch section 10g. The element section 20 is provided on the upper part of the switch section 10g.

[0091] 13, the switch section 10g has a configuration in which the gate electrode 2g does not overlap with the drain electrode 6 in a planar view. Therefore, a parasitic capacitance C3g generated by the gate electrode 2g and the drain electrode 6 overlapping with each other in a planar view becomes approximately 0 (zero).

[0092] When the switch section 10g is in the ON state, a voltage is applied to the source electrode 5 and the drain electrode 6 (including the channel formation film 4 therebetween), and a capacitor is formed between the terminal electrode 22 and the drain electrode 6, which overlap in a planar view, generating capacitance. On the other hand, when the switch section 10g is in the OFF state, a capacitor is not formed between the terminal electrode 22 and the drain electrode 6, which overlap in a planar view, so that the capacitance can be made approximately 0 (zero). However, if the parasitic capacitance C3g is not approximately 0 (zero), it will have a large effect on the capacitance when the switch section 10g is in the OFF state.

[0093] FIG. 14 shows the capacitance C OFF 14 is a diagram for explaining the relationship between the capacitance C of the electronic element 100g when the switch section 10g is in the OFF state and the parasitic capacitance C3g. OFF The vertical axis is set to 1.0×10 -15 F~1.0×10 -12 When F is approximately 0 (zero), the capacitance C of 100 g of electronic element OFF In other words, the electronic element 100g is configured so that the gate electrode 2g does not have a portion that overlaps with the drain electrode 6 in a plan view, and the parasitic capacitance C3g is reduced to 1.0×10 -12 It is preferable to set the value to F.

[0094] The configuration of the switch section 10g described in the electronic element 100g can be similarly applied to the switch sections of the electronic elements 100 to 100f, and the capacitance of the electronic element can be suppressed to approximately 0 (zero) when the switch section is in the OFF state.

[0095] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0096] 1 semiconductor substrate, 1a silicon substrate, 2 gate electrode, 2a control electrode terminal, 3 gate insulating film, 4 channel forming film, 5 source electrode, 5a, 22 terminal electrode, 6 drain electrode, 10 switch portion, 20 element portion, 21 dielectric, 22a terminal, 24 coil electrode, 25 non-magnetic ceramics, 100, 100a-e, 200 electronic element.

Claims

1. A switch portion constituting a field effect transistor; an element portion electrically connected to the switch portion and constituting a passive element; The switch unit is A source electrode; A drain electrode; a channel forming film formed so as to overlap at least a part of the source electrode and a part of the drain electrode; a gate insulating film formed on the channel forming film; a gate electrode formed on the gate insulating film, The element portion is a first terminal electrode electrically connected to the source electrode; and a second terminal electrode that constitutes the passive element between the drain electrode and the second terminal electrode.

2. The electronic device according to claim 1 , wherein the switch portion is provided on an upper part or a lower part of the device portion.

3. The electronic device according to claim 1 or 2, wherein the passive element is any one of a capacitor, an inductor, and a resistor.

4. The passive element is a capacitor, The element portion is Further comprising a dielectric layer overlying at least the drain electrode; 4. The electronic element according to claim 1, wherein the second terminal electrode overlaps with the drain electrode in a planar view, and the drain electrode and the dielectric form the capacitor together.

5. The gate electrode is formed on a semiconductor substrate, the gate insulating film is formed on the gate electrode and the semiconductor substrate; the channel formation film is formed on the gate insulating film, the source electrode and the drain electrode are formed on the channel forming film; the dielectric is formed only on the drain electrode; The electronic device according to claim 4 , wherein the second terminal electrode is formed only on the dielectric material.

6. The passive element is an inductor, The element portion is 4. The electronic element according to claim 1, further comprising a coil electrode electrically connected between the drain electrode and the second terminal electrode.

7. Instead of the drain electrode, a portion where the gate electrode and the channel formation film overlap in a plan view is used, 7. The electronic device according to claim 1, wherein the passive element is formed between the portion and the second terminal electrode.

8. 8. The electronic device according to claim 1, wherein the gate electrode does not have a portion overlapping with the drain electrode in a plan view.

9. Circuit wiring, A circuit device comprising: the electronic element according to any one of claims 1 to 8, which is electrically connected to the circuit wiring.

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