Semiconductor device

Abstract

A semiconductor device 100 is provided with a resistance changing element 102, an impedance circuit 104, and a logic circuit 110. The resistance changing element 102 has a resistance value that changes steeply at a predetermined threshold temperature. The impedance circuit 104 is connected in series with the resistance changing element 102 between a power supply line and a ground line. The logic circuit 110 receives a signal at a connection node of the resistance changing element 102 and the impedance circuit 104.

Description

Technical Field

[0001] The present disclosure relates to semiconductor devices.

Background Art

[0002] In various circuits such as integrated circuits, power devices, photonics, sensors, and μ-TAS (Total Analysis Systems) (hereinafter referred to as semiconductor devices), local temperature management is important. In conventional semiconductor devices, a temperature-sensitive element in which the resistance value or voltage drop continuously and monotonically changes with temperature, such as a PN junction (diode) or a thermistor, is used, and the voltage generated in the temperature-sensitive element is processed using an analog circuit such as a voltage comparator or an A / D converter (Non-Patent Documents 1 to 3).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0004] In the local temperature management of semiconductor devices, high-speed response, low power consumption, and small area are required rather than measurement accuracy. In conventional temperature management, since an analog circuit is used for the interface with the temperature-sensitive element, there are problems such as a large circuit area, a slow response speed, and high power consumption.

[0005] Also, the same problems have occurred when using sensors that detect environmental information other than temperature, such as pressure, gas atmosphere, magnetic field, electric field, light (illuminance), etc.

[0006] The present disclosure has been made in this situation, and an exemplary object of one aspect thereof is to provide a semiconductor device capable of detecting environmental information or transmitting signals at high speed and with low power consumption.

Means for Solving the Problems

[0007] One aspect of the present disclosure relates to a semiconductor device. The semiconductor device includes a resistance change element whose resistance value changes steeply according to the environment, an impedance circuit connected in series with the resistance change element between a constant voltage line and a ground line, and a logic circuit that receives a signal of a detection node that is a connection node between the resistance change element and the impedance circuit.

[0008] In addition, any combination of the above components, and those obtained by converting the expression of the present invention among devices, methods, systems, etc. are also effective as aspects of the present invention.

Effects of the Invention

[0009] According to the present invention, environmental information can be acquired at high speed and with low power consumption.

Brief Description of the Drawings

[0010]

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Best Mode for Carrying Out the Invention

[0011] (Summary of Embodiment) The summary of some exemplary embodiments of the present disclosure will be described. This summary simplifies and describes some concepts of one or more embodiments for the purpose of providing a basic understanding of the embodiments as a prelude to the detailed description to follow, and does not limit the scope of the invention or the disclosure. Also, this summary is not an all-inclusive summary of all possible embodiments and does not limit the essential components of the embodiments. For convenience, "one embodiment" may be used to refer to one embodiment (example or variation) or a plurality of embodiments (examples or variations) disclosed in this specification.

[0012] A semiconductor device according to one embodiment includes a resistance change element whose resistance value changes steeply according to the environment, an impedance circuit connected in series with the resistance change element between a constant voltage line and a ground line, and a logic circuit that receives a signal of a detection node that is a connection node between the resistance change element and the impedance circuit.

[0013] "The resistance value changes steeply" includes that the resistance value changes by one digit or more when a physical quantity characterizing the environment to be monitored is near a threshold value, or that the resistance value changes substantially in a stepwise manner, etc.

[0014] The voltage signal generated at the connection node between the resistance change element and the impedance circuit changes substantially in two binary values of high and low according to the magnitude relationship between the physical quantity to be monitored and the threshold value. That is, since the combination of the resistance change element and the impedance circuit behaves like a digital circuit, its output signal can be directly received by the logic circuit. In this configuration, an analog interface circuit is not required, so high speed, low power consumption, and area saving are possible.

[0015] The semiconductor device may further include a first switch connected in series with a series connection circuit of a resistance change element and an impedance circuit between a constant voltage line and a ground line. The first switch may be turned on during the sensing period. Thereby, the power consumption can be further reduced.

[0016] In one embodiment, the first switch may be controlled by a logic circuit.

[0017] In one embodiment, the constant voltage line may be a power supply line of the logic circuit.

[0018] In one embodiment, the logic circuit may include a flip-flop that receives a signal of a detection node.

[0019] In one embodiment, the flip-flop may be an RS flip-flop. The logic circuit may further include a logic gate that performs a logical operation on the voltage of the detection node and the voltage of a connection node between the first switch and the series connection circuit, and outputs the result to the reset input of the RS flip-flop.

[0020] In one embodiment, the semiconductor device may be configured to detect any one of temperature, voltage, magnetic field, pressure, light, and concentration of a specific substance.

[0021] In one embodiment, the semiconductor device may further include a functional block that performs a predetermined process. At least one of the process, task, state, operation mode, and operation environment of the functional block may change according to the output of the logic circuit.

[0022] In one embodiment, the resistance change element may have a temperature-dependent resistance value. The semiconductor device may further include a heater element disposed close to the resistance change element, and a drive circuit that drives the heater element in response to an input signal. Thereby, signal transmission using heat becomes possible between two insulated circuit blocks.

[0023] In one embodiment, the drive circuit may include a second switch having one end connected to the heater element and a power supply voltage applied to the other end.

[0024] In one embodiment, the heater element and the resistance change element may be stacked with an insulating layer therebetween. The insulating layer is preferably a high thermal conductivity insulator, and the heater element and the resistance change element are thermally coupled while being electrically insulated. The insulating layer may include AlN (aluminum nitride), C (diamond), Si (silicon), SiC (silicon carbide), AlO X (aluminum oxide), Si 3 N 4 (silicon nitride), etc.

[0025] In one embodiment, the periphery of the heater element and the resistance change element may be filled with a heat insulating material that is a low thermal conductivity insulator having a lower thermal conductivity than the insulating layer. Examples of the heat insulating material include SiO 2 (silicon dioxide), ZrO 2 (zirconium dioxide, zirconia), steatite, organic substances such as resin and rubber, porous materials such as silica gel, and powdery materials such as nanotube ceramics.

[0026] In one embodiment, the electrodes of the heater element and the resistance change element, and / or the wiring connected thereto may include a metal oxide having a low thermal conductivity. Specifically, the electrode / wiring may be formed of a low thermal conductivity metal such as VO 2 (vanadium dioxide) doped with W (tungsten), InGaZnO4 (IGZO), RuO 2 (ruthenium dioxide) doped with La (lanthanum), ITO (indium tin oxide), AZO (ZnO:Al), etc. This can prevent heat from escaping from the heater electrode to the outside.

[0027] In one embodiment, the semiconductor device may further include a high thermal conductivity region formed so as to surround, cover, or sandwich the periphery of the resistance change element and the low thermal conductivity insulator. Thereby, external heat noise can be blocked.

[0028] In one embodiment, a plurality of sets of heater elements and drive circuits may be provided. By driving a plurality of drive circuits according to a plurality of input signals, logical operations (logical sum and logical product) of the plurality of input signals can be performed.

[0029] In one embodiment, the resistive change element is VO 2 ,RENiO 3 (RE = La, Pr, Nd, Sm, Eu), Ti 2 O 3 , Ba 1-y Sr y TiO 3 , Ba 1-x Pb x TiO 3 and may include phase change oxide materials such as these.

[0030] (Embodiment) Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Further, the embodiments are illustrative and not restrictive of the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0031] In this specification, the phrase "member A is connected to member B" includes cases where member A and member B are physically directly connected, and cases where member A and member B are indirectly connected via other members that do not substantially affect their electrical connection state or impair the functions and effects achieved by their connection.

[0032] Similarly, the phrase "member C is provided between member A and member B" includes cases where member A and member C, or member B and member C are directly connected, as well as cases where they are indirectly connected via other members that do not substantially affect their electrical connection state or impair the functions and effects achieved by their connection.

[0033] In this specification, expressions such as "high thermal conductivity material", "high thermal conductivity insulator", and "high thermal conductivity metal" refer to materials with a thermal conductivity of 20 Wm -1 K -1 or higher. Also, in this specification, expressions such as "low thermal conductivity material", "low thermal conductivity insulator", and "low thermal conductivity metal" refer to materials with a thermal conductivity of 10 Wm -1 K -1 or lower.

[0034] (Embodiment 1) FIG. 1 is an equivalent circuit diagram of a semiconductor device 100A according to Embodiment 1. The semiconductor device 100A includes a resistance change element 102, an impedance circuit 104, and a logic circuit 110, and is integrated on a single substrate.

[0035] The resistance change element 102 is a metal-insulator transition material including VO 2 and the like, and the resistance value R TH changes steeply at a predetermined threshold temperature (also referred to as the transition temperature) T MIT . It is preferable that the resistance values R H and R L differ by one digit or more. FIG. 2 is a diagram showing the temperature dependence of the resistance value R MIT of the resistance change element 102. The resistance value R MIT of the resistance change element 102 has a low value R TH when the temperature T is higher than the threshold temperature T L , and has a high value R TH when the temperature T is lower than the threshold temperature T H , and transitions between the insulator and metal states with the threshold temperature T TH as the boundary. The resistance change element 102 has hysteresis, and the threshold temperature T TH transitions at two values T THH , T THL . As will be described later, the threshold temperature T TH can be adjusted according to the material of the resistance change element 102 and the material of the underlying layer (substrate) on which the resistance change element 102 is formed.

[0036] Return to FIG. 1. The impedance circuit 104 is connected in series with the resistance change element 102 between the constant voltage line 101 and the ground line. In this example, the constant voltage line 101 is a power supply line to which the power supply voltage V DD is supplied.

[0037] In FIG. 1, the impedance circuit 104 is shown by the symbol of resistance. However, the impedance circuit 104 may be a transistor that behaves as a current source in addition to a resistance element, or a combination of a resistance element and a transistor. The impedance R of the impedance circuit 104 0 is, L <R 0 <R H is selected to satisfy.

[0038] The voltage V at the connection node of the resistance change element 102 and the impedance circuit 104 OUT is represented by Equation (1). V OUT =V DD ×R MIT / (R 0 +R MIT ) When the temperature T of the resistance change element 102 is lower than the threshold temperature T TH , since R MIT =R H , the voltage level (high voltage V OUT ) of the output voltage V at that time is represented by Equation (2). H ) V H =V DD ×R H / (R 0 +R H ) …(2)

[0039] When the temperature T is higher than the threshold temperature T TH , since R MIT =R L , the voltage level (low voltage V OUT ) of the output voltage V at that time is represented by Equation (3). L ) V L =V DD ×R L / (R0 +R L ) …(3)

[0040] R L ≪R 0 ≪R H When the relationship of "≪R" holds, V H ≈V DD , V L ≈0V. That is, the voltage signal V OUT is a digital signal indicating whether the temperature T is higher or lower than the threshold value T TH . Therefore, in this specification, the series connection circuit of the resistance change element 102 and the impedance circuit 104 is referred to as the binary thermistor 106.

[0041] The logic circuit 110 is a combinational sequential circuit and receives the output signal V OUT of the binary thermistor 106, that is, the signal at the connection node of the resistance change element 102 and the impedance circuit 104. The logic circuit 110 can be composed of a combination of flip-flops, latches, inverters, and various logic gates, holds the state of the output signal V OUT and executes predetermined signal processing.

[0042] The above is the configuration of the semiconductor device 100A. FIG. 3 is a diagram for explaining the operation of the binary thermistor 106 in FIG. 1. The vertical axis represents the output voltage V OUT , and the horizontal axis represents the temperature T. Focusing on the process of temperature increase, when the temperature T is lower than the threshold value T THH , the output voltage V OUT is high (=V H ). When the temperature T exceeds the threshold value T THH , the output voltage V OUT transitions to low (V L ).

[0043] Focusing on the process of temperature decrease, when the temperature T is higher than the threshold value T THL , the output voltage V OUT is low (=V L ), and when the temperature T falls below the threshold value T THL , the output voltage V OUT is high (VH ) transitions to

[0044] The above is the operation of the semiconductor device 100A. According to this semiconductor device 100A, since the binary thermistor 106 behaves like a digital circuit, its output signal V OUT can be directly received by the logic circuit 110. That is, since the output signal V OUT of the binary thermistor 106 does not need to pass through an analog interface circuit or a front-end circuit such as an amplifier, a voltage comparator, or a D / A converter, it is possible to achieve high speed, low power consumption, and area saving.

[0045] For example, the binary thermistor 106 can be used as a thermal shutdown circuit (overheat protection circuit). The advantages of the semiconductor device 100A become clear by comparison with the following comparative technologies.

[0046] Comparative technology 1: The thermal shutdown circuit is composed of a combination of a thermistor and a voltage comparator that compares the voltage generated in the thermistor with a reference voltage (threshold voltage). In this case, the thermistor needs to be externally attached to the semiconductor device and does not directly monitor the chip temperature (junction) temperature of the semiconductor device. Also, the circuit area of the voltage comparator is large, and its power consumption is also large. There is also a response delay in the voltage comparator. In comparison, the semiconductor device 100A according to the embodiment is superior to comparative technology 1 in terms of size, power consumption, and speed.

[0047] Comparative Technique 2: The thermal shutdown circuit is configured using a PN junction (diode). A current flows through the PN junction according to the junction temperature. Alternatively, when the PN junction is biased with a constant current, a voltage drop dependent on temperature occurs across its two ends. The temperature-dependent electrical signal is compared with a reference voltage by a comparator, and an overheating state is detected. Also in Comparative Technique 2, since a comparator is required, the circuit area, power consumption, and response delay also increase. In comparison, the semiconductor device 100A according to the embodiment is superior to Comparative Technique 2 in terms of size, power consumption, and speed.

[0048] Also, in Comparative Techniques 1 and 2, since the threshold temperature is determined according to the reference voltage input to the comparator, when the reference voltage fluctuates, the threshold temperature also fluctuates. In addition, since the comparator has an input offset voltage that cannot be ignored, the threshold temperature also varies or fluctuates due to the influence of the input offset voltage. In contrast, in the semiconductor device 100A according to the embodiment, the threshold temperature T TH is not affected by the reference voltage or the input offset voltage of the comparator.

[0049] Also, the semiconductor device 100A according to the embodiment has the advantage that it can be mounted not only on an analog-digital hybrid circuit but also on a full-digital circuit.

[0050] Also, in the comparative technique, it is necessary to use a hysteresis comparator to prevent chattering, but in this embodiment, since the binary thermistor 106 itself has hysteresis, it also has the advantage of being resistant to chattering.

[0051] Subsequently, the results of fabricating and evaluating a sample of the resistance change element 102 will be described. FIG. 4 is a diagram showing the structure of the resistance change element 102. The resistance change element 102 includes a substrate 200, VO 2It has a stacked structure of layer 202 and electrodes 204 and 206, and the region sandwiched between the two electrodes 204 and 206 functions as the resistive change element 102. The gap length L between the two electrodes 204 and 206 corresponds to the length of the resistive change element 102, and the wiring width W of the two electrodes 204 and 206 corresponds to the width of the resistive change element 102.

[0052] Subsequently, the threshold temperature T TH will be described. The transition temperature of the MIT material varies in the range of -200°C to 80°C depending on the material, impurity concentration, etc. In other words, using these as design parameters, the threshold temperature T TH can be determined.

[0053] FIG. 5 is a diagram showing the temperature dependence of the resistivity of the resistive change element 102 in FIG. 4. As the substrate 200, three types of TiO 2 (001), TiO 2 (101), and Al 2 O 3 (0001) were used to create three types of samples. The film thickness t of the VO 2 layer in each sample is 9 nm for TiO 2 (001), 9 nm for TiO 2 (101), and 80 nm for Al 2 O 3 (0001). Also, W = 1 mm and L = 1 mm. The transition temperature varies among the three types of samples and is controlled in the range of 280 K to 360 K.

[0054] FIG. 6(a) is an atomic force microscope photograph of a sample of the resistive change element 102. This sample is downsized to an extent that can be integrated into a semiconductor chip, and the dimensions are L = 240 nm, W = 590 nm, and t = 6 nm. FIG. 6(b) is a diagram showing the temperature dependence of the resistance value R MIT of this sample. The transition temperature is 320 K, and the resistance value R MIT changes steeply.

[0055] FIG. 7(a) is a circuit diagram of a semiconductor device 100A according to an embodiment. A first switch SW1 is provided between a constant voltage line 101 and a binary thermostat 106. For example, the first switch SW1 may be composed of a P-channel MOSFET. During the sensing period, the first switch SW1 is turned on, and a sense voltage V SENSE (i.e., the power supply voltage V DD ) is supplied, enabling temperature comparison. During the non-sensing period when the first switch SW1 is off, no current flows through the binary thermostat 106, so the power consumption is zero.

[0056] The on and off states of the first switch SW1 may be controlled by a logic circuit 110. At the timing of determining the temperature, the logic circuit 110 may include a gate driver that turns on the first switch SW1 and turns it off during other periods.

[0057] In this embodiment, the constant voltage line 101 is a power supply line, and the power supply voltage V DD is also supplied to the logic circuit 110. The logic circuit 110 includes a combinational circuit 113 and an RS flip-flop 112. The output signal V OUT of the binary thermostat 106 is input to the set terminal of the RS flip-flop 112. The combinational circuit 113 performs a logical operation on the output signal V OUT and the sense signal V SENSE and inputs the result to the reset terminal of the RS flip-flop 112. For example, the combinational circuit 113 includes a NOR gate 114 and an inverter 116. The inverter 116 inverts the sense signal V SENSE . The NOR gate 114 generates a negative logical sum V OUT of the output signal V SENSE and the inverted signal of the sense signal V RESET . FIG. 7(b) is a truth table of the semiconductor device 100A in FIG. 7(a).

[0058] It is understood that the configuration of the logic circuit 110 in FIG. 7(a) is an example, and there are various modifications.

[0059] Figures 8(a) and 8(b) are the operation waveform diagrams of the semiconductor device 100A in Fig. 7(a). Fig. 8(c) is a diagram showing the characteristics of the semiconductor device 100A in Fig. 7(a). Note that the sensing speed is dominated by the delay in the logic circuit 110 rather than the RC delay in the binary thermistor 106.

[0060] Fig. 9 is a block diagram of a semiconductor device 100D according to an embodiment. The semiconductor device 100D is an ASIC (Application Specific Integrated Circuit), a microcontroller, a processor, etc. that execute predetermined signal processing, and includes a functional block 140.

[0061] The functional block 140 is the main circuit of the semiconductor device 100D. At least one of the processing, tasks, states, operation modes, and operation environments of the functional block 140 may change according to the output of the logic circuit 110, that is, the temperature. For example, according to the temperature range indicated by the output of the logic circuit 110, the power supply voltage of the functional block 140 may be switched, or the operating frequency may be switched. Alternatively, the functional block 140 may execute a predetermined process when the output of the logic circuit 110 indicates that it is within a predetermined temperature range. Also, the functional block 140 may switch its own functions, processes, and tasks according to the temperature range indicated by the output of the logic circuit 110.

[0062] (Embodiment 2) In Embodiment 1, the case where the binary thermistor 106 is used for temperature determination, such as in a thermal shutdown circuit, has been described, but it is not limited to this.

[0063] FIG. 10 is a circuit diagram of a semiconductor device 100B according to Embodiment 2. The semiconductor device 100B includes a heater element 120 and a drive circuit 122 in addition to a binary transistor 106 and a logic circuit 110. The heater element 120 is disposed in proximity to the resistance change element 102. As the heater element 120, a metal with low electrical conductivity such as Ni (nickel) or W (tungsten) can be used.

[0064] The drive circuit 122 drives the heater element 120 in response to an input signal V IN and controls the heating and cooling of the heater element 120. Note that a first switch SW1 may be inserted between the binary transistor 106 and the power supply line to intermittently apply the sense voltage V SENSE .

[0065] The above is the configuration of the semiconductor device 100B. FIG. 11 is a diagram showing the input / output characteristics of the semiconductor device 100B of FIG. 10. These input / output characteristics match those of an inverter.

[0066] According to this semiconductor device 100B, an input signal V IN , which is an electrical signal, is once converted into a thermal signal, and the thermal signal is again converted into an output signal V OUT , which is an electrical signal, and can be transmitted to the logic circuit 110. The heater element 120, the drive circuit 122, and the binary transistor 106 are referred to as an electrothermocoupler 130.

[0067] In an isolated power supply or the like, isolation between the primary side and the secondary side is required. Conventionally, a photocoupler or a pulse transformer has been used to transmit signals between the primary side and the secondary side. The electrothermocoupler 130 of FIG. 10 can also be used for such applications.

[0068] Figures 12(a) to (c) are circuit diagrams showing a configuration example of the drive circuit 122. The drive circuit 122 in Fig. 12(a) includes a second switch SW2. The second switch SW2 is, for example, a P-channel MOSFET, one end of which is connected to the heater element 120, and the other end is applied with a power supply voltage V DD and the input signal V IN is applied to the gate (control terminal). The input-output characteristics of the electrothermal coupler 130 in this case are of a non-inverting type in which the logic of the input signal V IN and the output signal V OUT match.

[0069] The drive circuit 122 in Fig. 12(b) includes a CMOS inverter. The drive circuit 122 in Fig. 12(c) includes a current source that can be switched on and off according to the input signal V IN .

[0070] Fig. 13 is a diagram showing a configuration example of a part of the electrothermal coupler 130. On the substrate 300, a VO 2 layer 302, which is a resistance change element 102, is formed. Further, an insulating layer 304 and a heater element 306 are laminated in this order on the VO 2 layer 302. As the insulating layer 304, a material that is electrically insulating and has a high thermal conductivity can be used.

[0071] A sample of the electrothermal coupler 130 having the structure of Fig. 13 was fabricated and its characteristics were evaluated. Fig. 14(a) is a photograph of the sample of the electrothermal coupler 130 of Fig. 13. The substrate 300 is TiO 2 (001), and the thickness of the VO 2 layer is 8 nm. The material of the heater element 306 is Ni (nickel), and as the insulating layer 304, Y 2 O 3 (yttrium oxide) with a thickness of 15 nm was formed.

[0072] Fig. 14(b) is a diagram showing the input-output characteristics of the sample of the electrothermal coupler 130. The horizontal axis represents the input signal V IN . The upper vertical axis represents the conductance, and the lower vertical axis represents the output signal V OUT . The characteristics in Fig. 14(b) are at an environmental temperature T of 280 Ke Next, it was measured with R 0 = 70 kΩ.

[0073] In order to perform high-speed signal transmission by the electrothermal coupler 130, the temperature of the electrothermal coupler 130 needs to change rapidly. FIG. 15 is a perspective view of the electrothermal coupler 130 suitable for high-speed signal transmission. In this example, the heater element 306 is formed of W (tungsten). Further, as the insulating layer 304, AlN (aluminum nitride), which is known as a high thermal conductivity material, is used. Further, the periphery of the laminated structure 301 including the heater element 306, the insulating layer 304, and the VO 2 layer 302 is covered with a heat insulating material 308 having a low thermal conductivity. As the heat insulating material 308, oxides such as SiO 2 can be used. The electrode portions (and / or the wirings connected thereto) at both ends of the VO 2 layer 302 are preferably formed of a low thermal conductivity metal such as W:VO 2 (tungsten-doped VO 2 ). Thereby, heat can be prevented from escaping from the electrodes of the VO 2 layer 302 (resistance change element 102) to the outside. Similarly, the electrodes of the heater element 306 and / or the wirings connected thereto are preferably formed of a low thermal conductivity material.

[0074] FIGS. 16(a) to (c) are cross-sectional views showing a preferred structure of the electrothermal coupler 130. As shown in FIG. 16(a), the electrothermal coupler 130 includes a high thermal conductivity region 312 formed so as to surround the laminated structure 301 of the heater element 306, the heater element 306, and the VO 2 layer 302. For example, the high thermal conductivity region 312 may be a wiring surrounding the laminated structure 301. The high thermal conductivity region 312 may be a wiring layer of a high thermal conductivity metal such as copper (Cu), silver (Ag), gold (Au), or aluminum (Al).

[0075] In FIG. 16(b), the high thermal conductivity region 312 is formed so as to cover the upper surface of the laminated structure 301.

[0076] As shown in FIG. 16(c), the stacked structure 301 is sandwiched between the upper high thermal conductivity layer 312A and the lower high thermal conductivity layer 312B.

[0077] As shown in FIGS. 16(a) to (c), by forming the high thermal conductivity region 312 around the stacked structure 301, external thermal noise can be blocked. Also, the Joule heat after signal transmission is completed can be quickly diffused and reset.

[0078] FIG. 17 is a diagram showing the simulation result of the thermal distribution of the electrothermal coupler 130 in FIG. 15. In FIG. 17, the thermal distributions after 0.02 ns, 0.2 ns, 0.4 ns, and 1 ns from heating are shown. The heater element is driven by a 0.2 ns pulse signal. This thermal distribution shows a cross section including the dashed line 310 in FIG. 15.

[0079] FIG. 18 is a simulation waveform diagram of the electrothermal coupler 130 in FIG. 15. The input signal V IN is a 0.2 ns pulse, and the power supply voltage V SENSE for the binary thermistor 106 is a 1 ns pulse. The bottom temperature is the temperature at the center of each slab of the heater of W, VO 2 layers. The output signal V OUT is asserted when VO 2 exceeds the transition temperature (320K). From this simulation result, it can be seen that ultra-high-speed signal transmission is possible.

[0080] (Embodiment 3) FIG. 19 is a circuit diagram of the semiconductor device 100C according to Embodiment 3. The semiconductor device 100C includes a plurality of N heater elements 120_1 to 120_N and N drive circuits 122_1 to 122_N corresponding to the N heater elements 120_1 to 120_N. The plurality of N heater elements 120_1 to 120_N are thermally coupled to a common binary thermistor 106. Each drive circuit 122_i (i = 1, 2,..., N) drives the corresponding heater element 120_i according to the corresponding input signal V IN _i.

[0081] According to this semiconductor device 100C, an output signal V can be generated by performing a logical operation on a plurality of input signals V IN _1 to V IN _N. The type of logical operation is not limited, and examples include logical sum, logical product, negative logical sum, negative logical product, exclusive logical sum, etc. The type of logical operation can be designed according to the configuration of the drive circuit 122. OUT

[0082] As described above, the present invention has been described based on the embodiments. These embodiments are illustrative, and it is understood by those skilled in the art that various modifications are possible for each component and the combination of each processing process, and such modifications are also within the scope of the present invention. Hereinafter, such modifications will be described.

[0083] (Modification Example 1) Regarding the electrothermal coupler 130, in Embodiment 2, the structure is such that the VO 2 layer 302 and the heater element 306 are laminated, but either the VO 2 layer 302 or the heater element 306 may be arranged on the upper side.

[0084] (Modification Example 2) Also regarding the electrothermal coupler 130, the VO 2 layer 302 and the heater element 306 may be arranged adjacent to each other in the lateral direction without being laminated.

[0085] (Modification Example 3) In the embodiment, the temperature sensing has been described, but the application of the present disclosure is not limited thereto. The resistance value of the oxidation MIT material changes steeply with a certain threshold as a boundary according to not only temperature but also voltage, magnetic field, pressure, light, concentration of a specific substance, etc. (hereinafter collectively referred to as environment) (Non-Patent Document 7). Therefore, the semiconductor device 100 described in the embodiment can be used for detecting voltage, magnetic field, pressure, light, concentration of substances such as gas and liquid, etc.

[0086] ​Based on the embodiments, the present invention has been described using specific terms. However, the embodiments merely illustrate the principles and applications of the present invention, and many modifications and arrangement changes are recognized within the scope that does not deviate from the idea of the present invention defined in the claims.

Industrial Applicability

[0087] This disclosure relates to semiconductor devices.

Explanation of Signs

[0088] 100 Semiconductor device 102 Resistance change element 104 Impedance circuit 106 Binary thermistor 110 Logic circuit 120 Heater element 122 Drive circuit 130 Electric thermal coupler 300 Substrate 301 Laminated structure 302 VO 2 Layer 304 Insulating layer 306 Heater element 308 Heat insulator 312 High thermal conductivity region

Claims

1. A resistance change element whose resistance value changes by one digit or more when the temperature crosses a threshold value, an impedance circuit connected in series with the resistance change element between a constant voltage line and a ground line, and a logic circuit connected to a detection node which is a connection node between the resistance change element and the impedance circuit, and receiving either a high or low binary state. A semiconductor device comprising the same.

2. Further comprising a first switch connected in series with a series connection circuit of the resistance change element and the impedance circuit between the constant voltage line and the ground line, The semiconductor device according to claim 1, wherein the first switch is turned on during a sensing period.

3. The semiconductor device according to claim 2, wherein the first switch is controlled by the logic circuit.

4. The semiconductor device according to any one of claims 1 to 3, wherein the constant voltage line is a power supply line of the logic circuit.

5. The semiconductor device according to any one of claims 1 to 3, wherein the logic circuit includes a flip-flop that receives a signal of the detection node.

6. The logic circuit is an RS flip-flop that receives a signal of the detection node, a logic gate that performs a logical operation on the voltage of the detection node and the voltage of a connection node between the first switch and the series connection circuit, and outputs the result to a reset input of the RS flip-flop. The semiconductor device according to claim 2 or 3, comprising the same.

7. The semiconductor device according to any one of claims 1 to 6, wherein the resistance change element is an oxide MIT (Metal-Insulator Transition) material.

8. Further comprising a functional block that performs a predetermined process, and wherein the process, task, state, operation mode, and operation environment of the functional block change according to the output of the logic circuit. The semiconductor device according to any one of claims 1 to 7.

9. The resistance change element has a temperature-dependent resistance value, a heater element provided on a semiconductor device on which the resistance change element is formed, and a drive circuit that drives the heater element in response to an input signal. The semiconductor device according to any one of claims 1 to 8, further comprising the same.

10. The semiconductor device according to claim 9, wherein the drive circuit includes a second switch having one end connected to the heater element and a power supply voltage applied to the other end.

11. The semiconductor device according to claim 9 or 10, wherein the heater element and the resistance change element are laminated with an insulating layer interposed therebetween.

12. The semiconductor device according to claim 11, wherein the periphery of the heater element and the resistance change element is filled with a heat insulating material having a lower thermal conductivity than that of the insulating layer.

13. The electrodes of the heater element and the resistance change element and / or the wiring connected thereto are VO doped with W (tungsten). ２ (vanadium dioxide), InGaZnO ４ (IGZO), RuO doped with La (lanthanum) ２ (ruthenium dioxide), ITO (indium tin oxide), AZO (ZnO:Al), and the semiconductor device according to any one of claims 9 to 12, characterized by containing a metal oxide that is any one of them.

14. The semiconductor device according to any one of claims 9 to 13, further comprising a high thermal conductivity region formed so as to surround, cover, or sandwich the periphery of the resistance change element.

15. The semiconductor device according to any one of claims 9 to 13, wherein a plurality of sets of the heater element and the drive circuit are provided.

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