A low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction

Abstract

The present invention provides a carrier wafer low-power temperature sensor based on a nitride semiconductor heterojunction, which includes a rectifying device and a resistive device. The rectifying device and the resistive device are fabricated on the same nitride semiconductor heterojunction. The rectifying device and the resistive device are electrically connected in series. Under an electrical bias voltage, the electrical properties of the rectifying device and the resistive device change with temperature: the resistance of the rectifying device decreases with increasing temperature after it is turned on, and the resistance of the resistive device increases with increasing temperature. The manufacturing process of the temperature sensor of the present invention is compatible with the nitride semiconductor heterojunction electronic device process. Without the need to additionally design new manufacturing processes and materials, the temperature detection and signal amplification functions on the same heterojunction chip can be realized, achieving the purpose of accurate, real-time, low-power chip temperature measurement and cost savings in manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor electronic devices, and particularly relates to a wafer low-power temperature sensor based on a nitride semiconductor heterojunction. Background Art

[0002] Among many temperature sensors, semiconductor temperature sensors have been widely used due to their many advantages such as accuracy, small size, and strong anti-interference ability. However, due to the limitations of material properties, the upper working temperature limit of temperature sensors made of traditional Si semiconductor materials is about 150 °C, which limits their application fields. Wide-bandgap nitride devices have advantages such as fast switching speed, low on-resistance, and can work at high temperatures, and have good application prospects in electronic power devices. Silicon-based nitride technology is the mainstream technology for current III-group nitride devices, with the dual advantages of low material cost and compatibility with silicon-based CMOS processes. Summary of the Invention

[0003] To solve the above problems, the present invention proposes a wafer low-power temperature sensor based on a nitride semiconductor heterojunction, which has the function of accurately, real-time, and low-power detecting the temperature of the wafer.

[0004] The technical solution of the present invention is as follows: A wafer low-power temperature sensor based on a nitride semiconductor heterojunction includes a rectifying device and a resistive device, both of which are fabricated on the same wafer nitride semiconductor heterojunction; the nitride semiconductor heterojunction is formed on a support layer; the rectifying device includes a two-dimensional electron gas channel, a Schottky contact layer adjacent to the upper surface of the nitride semiconductor heterojunction, and an ohmic contact layer connected to the two-dimensional electron gas channel; the resistive device includes a two-dimensional electron gas channel and ohmic contact layers at both ends connected to the two-dimensional electron gas channel; a metal wire layer electrically connects the positive electrode of the rectifying device and the negative electrode of the resistive device in series and leads out an output terminal; wherein, the nitride semiconductor heterojunction includes a channel layer with a first bandgap and a barrier layer with a second bandgap larger than the first bandgap, the barrier layer is formed on the channel layer, and the channel layer is formed on the support layer; an isolation area is provided between the rectifying device and the resistive device to isolate the rectifying device and the resistive device.

[0005] Further, the two-dimensional electron gas channel is formed at the interface between the channel layer and the barrier layer due to the polarization effect of the two materials of the channel layer and the barrier layer; the material of the channel layer and the material of the barrier layer are both group III nitrides.

[0006] Further, the positive electrode of the rectifying device is the Schottky contact layer, the negative electrode of the rectifying device is the ohmic contact layer; the negative electrode of the resistive device is the ohmic contact layer at one end.

[0007] Furthermore, when the rectifying device is under an electrical bias voltage and the bias voltage is relatively small, there is a potential barrier in the Schottky contact layer of the rectifying device, the rectifying device is not turned on, the temperature sensor does not work and the power consumption is zero; when the bias voltage is greater than the turn-on voltage of the rectifying device, the Schottky potential barrier is overcome and the rectifying device is turned on, and the temperature sensor starts to work.

[0008] Furthermore, the value of the turn-on voltage of the rectifying device depends on the work function of the metal in the Schottky contact layer.

[0009] Furthermore, the resistance of the rectifying device after being turned on is affected by the contact area between the metal in the Schottky contact layer and the barrier layer. The larger the area, the smaller the resistance.

[0010] Furthermore, the resistance of the rectifying device after being turned on has a negative temperature characteristic. As the temperature increases, the thermionic emission through the potential barrier is enhanced and the resistance after being turned on decreases.

[0011] Furthermore, the resistive device changes the width or length of the two-dimensional electron gas channel, and the resistance of the resistive device changes accordingly.

[0012] Furthermore, the resistance of the resistive device has a positive temperature characteristic. As the temperature increases, the carrier mobility decreases accordingly and the resistance value increases.

[0013] Furthermore, under an electrical bias voltage, when the temperature increases, the voltages of the resistive device and the rectifying device of the temperature sensor are redistributed, and the voltage value at the output end changes.

[0014] Furthermore, under an electrical bias voltage, the voltage division of the rectifying device decreases with the increase of temperature, and the power consumption decreases with the increase of temperature.

[0015] Furthermore, the temperature sensor shares a heterojunction carrier with a traditional group III nitride heterojunction electronic device, and the manufacturing processes are mutually compatible.

[0016] The beneficial effects of the present invention at least include:

[0017] 1) The temperature sensor of the present invention can monitor the temperature change in real time and has accurate and real-time temperature measurement characteristics.

[0018] 2) The temperature sensor of the present invention can achieve the advantages of reducing cost, reducing volume, and decreasing power consumption at high temperatures.

[0019] 3) The present invention adopts silicon-based nitride technology to simultaneously integrate resistive devices and rectifying devices on the same wafer, fabricating a low-power temperature sensor on a carrier wafer based on a nitride semiconductor heterojunction. Utilizing the characteristic that the current-voltage (I-V) curves of the two are opposite when the temperature changes, the temperature signal is converted into an electrical signal to achieve the capture and identification of temperature information.

[0020] 4) The low-power temperature sensor on a carrier wafer based on a nitride semiconductor heterojunction of the present invention is compatible with the integrated circuit manufacturing process and can be used to monitor and manage the internal temperature of the chip to prevent overheating of power devices. Description of the Drawings

[0021] Figure 1 It is a schematic cross-sectional structure diagram of the temperature sensor described in the embodiment of the present invention;

[0022] Figure 2 It is a top view of the structure of the temperature sensor described in the embodiment of the present invention;

[0023] Figure 3 It is a graph showing the variation of the current-voltage (I-V) characteristic of the resistive device described in the embodiment of the present invention with temperature;

[0024] Figure 4 It is a graph showing the variation of the current-voltage (I-V) characteristic of the rectifying device described in the embodiment of the present invention with temperature;

[0025] Figure 5 It is a graph showing the variation of the output voltage with temperature when the operating voltage of the temperature sensor described in the embodiment of the present invention is 4V;

[0026] Figure 6 It is a graph showing the variation of the power consumption with temperature when the operating voltage of the temperature sensor described in the embodiment of the present invention is 4V.

[0027] Wherein: support layer 1, channel layer 2, barrier layer 3, two-dimensional electron gas channel 4, ohmic contact layer 5, Schottky contact layer 6, metal wire layer 7, isolation region 8, rectifying device 9, resistive device 10. Detailed Embodiments

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Such as Figure 1-2As shown, the temperature sensor of the embodiment of the present invention includes a rectifying device 9 and a resistive device 10, which are fabricated on the same nitride semiconductor heterojunction. The rectifying device 9 and the resistive device 10 are isolated by an isolation region 8. The nitride semiconductor heterojunction is formed on a support layer 1. The rectifying device 9 includes: a two-dimensional electron gas channel 4, a Schottky contact layer 6 adjacent to the upper surface of the nitride semiconductor heterojunction, and an ohmic contact layer 5 connected to the two-dimensional electron gas channel. The resistive device 10 includes: a two-dimensional electron gas channel 4, and two-terminal ohmic contact layers 5 connected to the two-dimensional electron gas channel 4. A metal wire layer 7 electrically connects the positive electrode of the rectifying device 9 and the negative electrode of the resistive device 10 in series and leads out an output terminal. The positive electrode of the rectifying device 9 is the Schottky contact layer 6, and the negative electrode of the rectifying device 9 is the ohmic contact layer 5; the negative electrode of the resistive device 10 is the ohmic contact layer 5 at one end. Wherein, the nitride semiconductor heterojunction includes a channel layer 2 having a first bandgap, a barrier layer 3 having a second bandgap larger than the first bandgap, the barrier layer 3 is formed on the channel layer 2, and the channel layer 2 is formed on the support layer 1; further includes the two-dimensional electron gas channel 4 formed at the interface between the channel layer 2 and the barrier layer 3 due to the polarization effect of the two materials of the channel layer 2 and the barrier layer 3. The isolation region 8 isolates the rectifying device 9 and the resistive device 10. The two-dimensional electron gas channel 4 is a 2DEG channel. The support layer 1 includes a substrate layer, a transition layer, a buffer layer and other structures. In terms of the electrode pattern, for the sake of simplification in this description, the electrodes are shown as squares.

[0030] Wherein, the support layer 1 has a transition layer, which plays an important role in reducing current collapse caused by lattice coefficient mismatch, defects or trap effects, and reducing longitudinal leakage, etc., which is not shown in this example. The semiconductor materials for the channel layer 2 and the barrier layer 3 are group III nitrides, which include but are not limited to GaN, AlGaN, InAlN, etc. There is no specific requirement for the specific composition.

[0031] In the embodiment of the present invention, the resistive device 10 and the rectifying device 9 exhibit opposite temperature characteristics with temperature change. For details, see Figure 3 and Figure 4 . Figure 3 and Figure 4 are respectively the graphs of the current-voltage (I-V) characteristics of the resistive device 10 and the rectifying device 9 of the embodiment of the present invention changing with temperature.

[0032] As Figure 3As shown, the resistance value of the resistive device 10 has a positive temperature characteristic. As the temperature increases, the carrier mobility decreases, and the resistance value increases. In the current-voltage (I-V) characteristic diagram, as the temperature increases, the current decreases. Among them, the resistive device 10 changes the width or length of the two-dimensional electron gas channel 4, and the resistance value changes accordingly. The resistance values of different resistive devices will change the output characteristics and overall power consumption of the temperature sensor.

[0033] As Figure 4 shown, the resistance after the rectifying device 9 is turned on has a negative temperature characteristic. As the temperature increases, the thermionic emission through the barrier is enhanced, and the resistance after being turned on decreases. In the current-voltage (I-V) characteristic diagram, as the temperature increases, the current after the rectifying device 9 is turned on increases accordingly. Among them, the magnitude of the turn-on voltage of the rectifying device 9 depends on the work function of the metal of the Schottky contact layer 6; the larger the work function, the larger the turn-on voltage; the resistance after the rectifying device 9 is turned on is affected by the contact area between the metal of the Schottky contact layer 6 and the barrier layer 3, and the larger the area, the smaller the resistance. Different turn-on voltages and resistance values after being turned on will change the output characteristics and overall power consumption of the temperature sensor. When the electrical bias voltage is small, there is a barrier in the Schottky contact layer 6 of the rectifying device 9, and the rectifying device 9 is not turned on; when the bias voltage is greater than the turn-on voltage of the rectifying device 9, the Schottky barrier is overcome, and the rectifying device 9 is turned on.

[0034] Figure 5 is the characteristic diagram of the output voltage varying with temperature of the wafer low-power temperature sensor based on the nitride semiconductor heterojunction when the working voltage is 4V. Under a fixed electrical bias voltage, as the temperature changes, due to the opposite temperature characteristics of the rectifying device 9 and the resistive device 10, the voltages across the resistive device 10 and the rectifying device 9 are redistributed, and the voltage value at the output end changes accordingly. In Figure 5 it, the output voltage decreases basically linearly as the temperature increases.

[0035] Figure 6 is the characteristic diagram of the power consumption varying with temperature of the temperature sensor of the present invention when the working voltage is 4V. Since the rectifying device 9 has a certain turn-on voltage for operation, and the resistance of the resistive device 10 increases as the temperature increases, under a fixed electrical bias voltage, the temperature sensor has the characteristic of reduced power consumption at high temperatures.

[0036] The preparation process of the wafer low-power temperature sensor based on the nitride semiconductor heterojunction of the present invention is as follows:

[0037] 1. Deposition: Use methods such as metal-organic chemical vapor deposition to epitaxially grow a nitride semiconductor heterojunction on the support layer 1. The materials used include but are not limited to GaN, AlGaN, InAlN, etc., and a two-dimensional electron gas channel 4 is formed at the interface of the heterojunction.

[0038] 2. Isolation: Isolate the two-dimensional electron gas channel 4 to which the resistive device 10 and the rectifying device 9 belong. The isolation method is not limited to ICP dry etching or ion implantation, etc.

[0039] 3. Ohmic contact layer 5: The cathode metal electrode of the rectifying device 9 and the metal electrodes at both ends of the resistive device 10 (regardless of anode and cathode) are both ohmic contact layer 5. Metals such as titanium, aluminum, nickel, and gold are used. First, deposit the metal, and then perform rapid annealing for metal heat treatment to jointly form the ohmic contact layer 5 with the two-dimensional electron gas channel 4.

[0040] 4. Schottky contact layer 6: The anode metal electrode of the rectifying device 9 forms a Schottky contact layer 6 with the barrier layer. The higher the energy barrier height of the Schottky contact layer 6, the lower the leakage current before the rectifying device 9 is turned on. Therefore, a contact metal with a higher work function, such as Ni, Pt, Pd, is selected. First, deposit the contact metal, and then perform rapid annealing for metal heat treatment to enhance the adhesion between the Schottky electrode and the material, thereby forming the Schottky contact layer 6.

[0041] 5. Metal wire layer: Electrically connect the negative electrode of the resistive device 10 and the positive electrode of the rectifying device 9 with a metal wire layer 7. Use techniques such as evaporation and sputtering to deposit a metal wire layer 7 on the above-mentioned ohmic contact layer 5 and Schottky contact layer 6.

[0042] Above, the wafer low-power temperature sensor based on the nitride semiconductor heterojunction is obtained.

[0043] The wafer low-power temperature sensor based on the nitride semiconductor heterojunction and its manufacturing process according to the present invention are compatible with the nitride semiconductor heterojunction electronic device process, and can realize the integration of a full-nitride semiconductor wafer temperature sensing integrated circuit with accurate and real-time temperature detection and signal amplification functions on the same chip.

[0044] In summary, a wafer low-power temperature sensor based on the nitride semiconductor heterojunction proposed by the present invention can achieve accurate detection of temperature changes under a relatively low operating voltage, taking into account cost, process, and structure, and also having the advantage of reduced power consumption at high temperatures.

[0045] Above, a wafer low-power temperature sensor based on the nitride semiconductor heterojunction proposed by the present invention has been introduced in detail. The above embodiments are only used to illustrate the technical idea of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the present invention.

Claims

1. A low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction, characterized in that: It includes a rectifying device and a resistive device, both of which are fabricated on the same nitride semiconductor heterojunction; the nitride semiconductor heterojunction is formed on a support layer; the rectifying device includes a two-dimensional electron gas channel, a Schottky contact layer adjacent to the upper surface of the nitride semiconductor heterojunction, and an ohmic contact layer connected to the two-dimensional electron gas channel; the resistive device includes a two-dimensional electron gas channel and ohmic contact layers at both ends connected to the two-dimensional electron gas channel; a metal wire layer electrically connects the positive electrode of the rectifying device and the negative electrode of the resistive device in series and leads out an output terminal; wherein, the nitride semiconductor heterojunction includes a channel layer with a first bandgap and a barrier layer with a second bandgap larger than the first bandgap, the barrier layer is formed on the channel layer, and the channel layer is formed on the support layer; there is an isolation region between the rectifying device and the resistive device to isolate the rectifying device and the resistive device; The two-dimensional electron gas channel is formed at the interface between the channel layer and the barrier layer due to the polarization effects of the two materials of the channel layer and the barrier layer; The positive electrode of the rectifying device is the Schottky contact layer, and the negative electrode of the resistive device is the ohmic contact layer at one end.

2. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 1, wherein: The material of the channel layer and the material of the barrier layer are both group III nitrides.

3. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 1, characterized in that: The positive electrode of the rectifying device is the Schottky contact layer, and the negative electrode of the rectifying device is the ohmic contact layer; the negative electrode of the resistive device is the ohmic contact layer at one end.

4. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, characterized in that: When the rectifying device is under an electrical bias and the bias is small, there is a barrier at the Schottky contact layer of the rectifying device, the rectifying device is not turned on, the temperature sensor does not work and the power consumption is zero; when the bias is greater than the turn-on voltage of the rectifying device, the Schottky barrier is overcome and the rectifying device is turned on, and the temperature sensor starts to work.

5. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, wherein: The value of the turn-on voltage of the rectifying device depends on the work function of the metal of the Schottky contact layer.

6. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, characterized in that: The resistance of the rectifying device after being turned on is affected by the contact area between the metal of the Schottky contact layer and the barrier layer. The larger the area, the smaller the resistance.

7. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, characterized in that: The resistance of the rectifying device after being turned on has a negative temperature characteristic. As the temperature increases, the thermionic emission through the barrier is enhanced and the resistance after being turned on decreases.

8. The temperature sensor with low power consumption for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, characterized in that: The resistive device changes the width or length of the two-dimensional electron gas channel, and the resistance of the resistive device changes accordingly.

9. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 3, characterized in that: The resistance of the resistive device has a positive temperature characteristic. As the temperature increases, the carrier mobility decreases and the resistance value increases.

10. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 1, wherein: Under an electrical bias, when the temperature increases, the voltages of the resistive device and the rectifying device of the temperature sensor are redistributed, and the voltage value at the output terminal changes.

11. The temperature sensor with low power consumption for the carrier wafer based on a nitride semiconductor heterojunction according to claim 1, characterized in that: Under an electrical bias, the voltage division of the rectifying device decreases with the increase of temperature, and the power consumption decreases with the increase of temperature.

12. The low-power temperature sensor for a carrier wafer based on a nitride semiconductor heterojunction according to claim 1, wherein: The temperature sensor shares a heterojunction carrier with traditional group III nitride heterojunction electronic devices, and the manufacturing processes are mutually compatible.

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