Method for recovering a transistor and semiconductor device

Abstract

The present disclosure provides a transistor recovery method and a semiconductor device, and relates to the technical field of semiconductors. The transistor recovery method comprises: in the case that the temperature of a transistor to be recovered is higher than a preset temperature, applying a first voltage between the gate electrode and the bottom electrode of the transistor to be recovered, wherein the voltage applied between the gate electrode and the bottom electrode of the transistor to be recovered in the working state is defined as a second voltage, and the first voltage and the second voltage are opposite in sign. Using the transistor recovery method in the present disclosure, the influence of the hot electron induced penetration effect can be effectively reduced or eliminated, the off-state leakage current of the transistor is reduced, the off-state characteristics of the transistor and the semiconductor device are optimized, and the reliability of the semiconductor device is improved.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and in particular to methods for recovering transistors and semiconductor devices. Background Technology

[0002] As the integration density of semiconductor devices increases, process technology enters the deep submicron stage, and the size of semiconductor devices continues to shrink, the hot electron-induced punch-through (HEIP) effect in transistors becomes more severe. This leads to increased turn-off leakage current, resulting in increased standby current and causing problems such as deteriorated off-state characteristics and increased static power consumption during use. Furthermore, the HEIP effect can cause logic state confusion in digital circuits and memory cells, reducing the reliability and lifespan of semiconductor devices. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail in this disclosure. This overview is not intended to limit the scope of the claims.

[0004] This disclosure provides a method for recovering a transistor and a semiconductor device.

[0005] According to a first aspect of the present disclosure, a method for recovering a transistor is provided, the method comprising:

[0006] When the temperature of the transistor to be recovered is higher than a preset temperature, a first voltage is applied between the gate and bottom electrode of the transistor to be recovered. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage, and the first voltage has the opposite sign to the second voltage.

[0007] According to some embodiments of this disclosure, the amplitude of the first voltage is 0.3 to 0.6 times the amplitude of the second voltage.

[0008] According to some embodiments of this disclosure, the recovery method includes:

[0009] When the temperature of the transistor to be recovered is higher than the preset temperature, the potentials of the source, drain, and bottom electrodes of the transistor to be recovered are made the same.

[0010] According to some embodiments of this disclosure, the recovery method includes:

[0011] When the transistor to be recovered is in the working state, the voltage applied between the source and drain of the transistor to be recovered is a third voltage;

[0012] The recovery method further includes:

[0013] When the temperature of the transistor to be recovered is higher than the preset temperature, a fourth voltage is applied between at least one of the source and drain of the transistor to be recovered and the bottom electrode. The amplitude of the fourth voltage is 0.8 to 1.2 times the amplitude of the third voltage, and the fourth voltage has the opposite sign to the third voltage.

[0014] According to some embodiments of this disclosure, the recovery method further includes:

[0015] The duration for which the first voltage is applied to the transistor to be recovered is controlled to be a preset duration;

[0016] The preset duration ranges from (0, 1000) and is measured in seconds.

[0017] According to some embodiments of this disclosure, the preset temperature ranges from [50, 150], in degrees Celsius.

[0018] According to some embodiments of this disclosure, the recovery method further includes:

[0019] The temperature of the transistor to be restored is detected, and it is determined whether the temperature of the transistor to be restored is higher than the preset temperature;

[0020] If so, apply the first voltage between the gate and bottom electrode of the transistor to be recovered;

[0021] If not, the transistor to be restored is heated to make and / or maintain the temperature of the transistor to be restored above the preset temperature.

[0022] According to some embodiments of this disclosure, the recovery method further includes:

[0023] The threshold voltage of the detected transistor is determined to be the transistor to be recovered when the threshold voltage exceeds a preset voltage threshold; and / or,

[0024] The turn-off leakage current of the transistor is detected. When the turn-off leakage current is greater than or equal to a preset current threshold, the transistor is determined to be the transistor to be recovered.

[0025] According to some embodiments of this disclosure, the recovery method further includes:

[0026] The cumulative operating time of the transistor is detected. When the cumulative operating time is greater than or equal to a preset operating time, the transistor is determined to be the transistor to be recovered.

[0027] According to some embodiments of this disclosure, the transistor is a metal-oxide-semiconductor field-effect transistor.

[0028] A second aspect of this disclosure provides a semiconductor device, comprising:

[0029] transistor;

[0030] A recovery circuit, coupled to the transistor, is configured to apply a first voltage between the gate and bottom electrode of the transistor to be recovered when the transistor is a transistor to be recovered and the temperature of the transistor to be recovered is higher than a preset temperature. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage, and the first voltage has the opposite sign to the second voltage.

[0031] According to some embodiments of this disclosure, the semiconductor device further includes:

[0032] A temperature sensing circuit is configured to detect the temperature of the transistor to be recovered and determine whether the temperature of the transistor to be recovered is higher than the preset temperature.

[0033] According to some embodiments of this disclosure, the semiconductor device includes a detection circuit configured to detect a threshold voltage and / or a turn-off leakage current of the transistor to determine whether the transistor is the transistor to be recovered; and / or,

[0034] The detection circuit is configured to detect the cumulative operating time of the transistor to determine whether the transistor is the transistor to be recovered.

[0035] According to some embodiments of this disclosure, the semiconductor device further includes:

[0036] A heating circuit is configured to heat the transistor to be restored so that the temperature of the transistor to be restored is higher than the preset temperature.

[0037] According to some embodiments of this disclosure, the semiconductor device further includes:

[0038] A timing circuit is configured to control the duration for which the first voltage is applied to the transistor to be restored.

[0039] The transistor recovery method provided in this disclosure has the following beneficial effects: when the temperature of the transistor to be recovered is higher than a preset temperature, by adding a first voltage with the opposite sign to the second voltage in the working state between the gate and the bottom electrode, the influence of the hot electron-induced penetration effect can be effectively reduced or eliminated, the turn-off leakage current of the transistor can be reduced, the off-state characteristics of the transistor and semiconductor device can be optimized, and the reliability of the semiconductor device can be improved.

[0040] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of these embodiments. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the present disclosure, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without inventive effort.

[0042] Figure 1 This is a schematic diagram of the hot electron-induced breakdown effect.

[0043] Figure 2 This is a schematic diagram of a planar transistor.

[0044] Figure 3 This is a flowchart illustrating a transistor recovery method according to an exemplary embodiment.

[0045] Figure 4 This is a flowchart illustrating a transistor recovery method according to an exemplary embodiment.

[0046] Figure 5 It is a graph showing the relationship between gate voltage and drain current obtained by recovering the transistor using existing recovery methods.

[0047] Figure 6 It is a graph showing the relationship between the gate voltage and the drain current obtained by recovering the transistor using the transistor recovery method in the exemplary embodiment.

[0048] Figure 7 It is a graph showing the relationship between the gate voltage and the drain current obtained by recovering the transistor using the transistor recovery method in the exemplary embodiment.

[0049] Figure 8 This is a schematic diagram illustrating the extraction of thermionic electrons under the action of a strong electric field, as shown in an exemplary embodiment.

[0050] Figure 9 This is a block diagram of a semiconductor device according to an exemplary embodiment. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the disclosed embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0052] As chip size continues to shrink, the supply voltage and operating voltage of the chip do not decrease proportionally with changes in channel length and gate oxide thickness. This leads to a significant increase in the electric field strength of the transverse and longitudinal electric fields within the channel. Under the influence of this high electric field, the velocity of charge carriers increases, transforming them into high-energy hot carriers. When the energy of these hot carriers is sufficiently high, they leave the silicon substrate and are directly injected into the gate oxide layer, forming a hot carrier injection (HCI) effect. This effect alters the threshold voltage and affects the reliability of semiconductor devices, ultimately leading to circuit failure.

[0053] like Figure 1 As shown, taking a P-type transistor as an example, it includes an active region 11, a gate 10, and a shallow trench isolation structure 12. The gate 10 includes a gate oxide layer (not shown in the figure). When forming trenches on the semiconductor substrate, a shallow trench isolation (STI) process with an insulating film is used. An oxide layer (such as silicon dioxide) and a nitride layer (such as silicon nitride) are formed in the shallow trench isolation structure 12. Hot electrons can easily enter the interface between the nitride layer and the oxide layer, forming a hot electron accumulation region. The hot electron accumulation region leads to a shortening of the effective channel length of the channel region and the formation of a leakage path. The trapped hot electrons cause the hot electron-induced punchthrough (HEIP) effect. The HEIP effect causes current to be generated in the channel region of the active region 11 even when no voltage is applied to the gate of the P-type transistor, resulting in a sharp increase in the turn-off leakage current of the transistor, which in turn leads to an increase in standby current. During use, the semiconductor device exhibits problems such as deterioration of off-state characteristics and increased static power consumption. Meanwhile, the hot electron-induced punch-through effect of transistors can also cause logic state confusion in digital circuits and memory cells, reducing the reliability and lifespan of semiconductor devices.

[0054] Bias temperature instability (BTI) is one of the key issues affecting the reliability of integrated circuit devices. Bias temperature instability includes negative-bias temperature instability (NBTI) and positive-bias temperature instability (PBTI), which refer to the degradation effects on the electrical characteristics of a transistor, such as threshold voltage drift and saturation current, when a bias voltage is applied to the transistor gate under certain temperature conditions. With the continuous shrinking of gate length and oxide layer thickness, the impact of bias temperature instability on semiconductor devices becomes increasingly significant, becoming one of the main factors contributing to device degradation. For semiconductor devices such as silicon (Si) or silicon carbide (SiC) transistors, bias temperature instability can cause significant variability in device performance. For example, negative bias temperature instability can cause significant changes or drift in the threshold voltage of SiC devices operating under specific conditions. NBTI in SiC devices is considered to be a result of interface charge trapping (e.g., oxide charge), which may be caused by prolonged operation of the device under elevated temperatures and specific bias conditions.

[0055] To alleviate a series of problems caused by the hot carrier injection effect, hot electron-induced punch-through effect, and bias temperature instability, this disclosure provides a transistor recovery method. When the temperature of the transistor to be recovered is higher than a preset temperature, a first voltage is applied between the gate and bottom electrode of the transistor to be recovered. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage. The first voltage and the second voltage have opposite signs, thereby improving the threshold voltage, reducing the turn-off leakage current of the transistor, optimizing the turn-off characteristics of the transistor and semiconductor device, and improving the reliability and service life of the semiconductor device.

[0056] According to an exemplary embodiment of this disclosure, a transistor recovery method is provided. This recovery method can be applied to the recovery process after aging experiments on semiconductor devices (including transistors) to restore the electrical performance of the semiconductor device and improve its reliability. This method can also be applied during the use of semiconductor devices (including transistors). For example, after prolonged use, the transistors of semiconductor devices may exhibit bias temperature instability, hot electron-induced punch-through, etc., severely affecting the reliability of the semiconductor device. The transistor recovery method of this embodiment can then be used to perform a recovery operation on the transistor, thereby extending its lifespan and improving its reliability.

[0057] The transistor recovery method in this embodiment includes:

[0058] When the temperature of the transistor to be recovered is higher than a preset temperature, a first voltage is applied between the gate and bottom electrode of the transistor to be recovered. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage. The first voltage and the second voltage have opposite signs. That is, one of the first voltage and the second voltage is a positive voltage, and the other is a negative voltage, so that the transistor to be recovered is in a state opposite to the operating state.

[0059] Specifically, when the above-mentioned transistor recovery method is applied to an aging experiment, the transistor to be recovered is one that has undergone the aging experiment and may exhibit hot carrier injection effect or hot electron-induced punch-through effect, requiring recovery. When the above-mentioned transistor recovery method is applied to the long-term use of semiconductor devices, the transistor to be recovered is one that has already experienced or may experience bias temperature instability.

[0060] In this embodiment, the recovery method requires the temperature of the transistor to be recovered to be higher than a preset temperature, such as [50, 150] degrees Celsius. When the temperature of the transistor to be recovered is higher than the preset temperature, it can provide energy to the hot electrons to a certain extent, helping them to be extracted from the hot electron accumulation region, the gate oxide layer, or the boundary between the gate and the transistor. It is understood that in this embodiment, the recovery method applies a voltage with the opposite sign to the voltage in the operating state between the gate and the bottom electrode of the transistor to be recovered, so that the transistor is in a state opposite to its operating state. This plays a major role in extracting the hot electrons from the hot electron accumulation region, the gate oxide layer, or the boundary between the gate and the transistor. The temperature of the transistor to be recovered being higher than the preset temperature plays a supporting role.

[0061] In this embodiment, the transistor to be recovered is a metal-oxide-semiconductor field-effect transistor (MOSFET), which can be either a P-type or an N-type MOSFET. To better illustrate the method in this embodiment, as follows... Figure 2 As shown, taking a planar transistor as an example, the structure of the transistor is explained. The planar transistor includes a substrate 14, in which a source 13 and a drain 15 are formed. A channel region 16 is formed between the source 13 and the drain 15. A gate 10 is formed above the substrate 14. The substrate 14, source 13, drain 15, and gate 10 together form a four-terminal device. The source 13, drain 15, and channel region 16 constitute... Figure 1The active region 11 shown in the figure has a substrate 14 that serves as the bottom electrode when a voltage is applied. Furthermore, the use of a planar transistor in this embodiment is for ease of understanding only and does not constitute a limitation on the type of transistor. The transistor in this embodiment can be a Lateral Field Effect Transistor (LFET), i.e., a planar transistor; or a Vertical Field Effect Transistor (VFET), such as a P-type VFET and an N-type VFET. When designing a semiconductor cell formed by a VFET, it is usually necessary to provide an additional gate structure or fin structure next to the gate structure on which the VFET is formed, so that the metal lines and / or vias connecting the contact structure of the VFET can be placed on the additional gate structure or fin structure to transmit signals.

[0062] During the recovery process of the transistor to be recovered, a first voltage is applied between the gate and the substrate (i.e., the bottom electrode). The first voltage is actually the difference between the voltage applied to the gate and the voltage between the gate and the substrate. For example, if the voltage applied to the substrate is 0V and the voltage applied to the gate is 3V, then the first voltage is 3V; or, if the voltage applied to the substrate is 1V and the voltage applied to the gate is 3V, then the first voltage is 2V. The voltage applied between the gate and the substrate of the transistor to be recovered in its operating state is defined as a second voltage. The second voltage is actually the difference between the voltage applied to the gate and the substrate. For example, if the voltage applied to the substrate is 0V and the voltage applied to the gate is -3V, then the second voltage is -3V; or, if the voltage applied to the substrate is 1V and the voltage applied to the gate is -3V, then the second voltage is -4V. In this embodiment, the first and second voltages have opposite signs, i.e., one is a positive voltage and the other is a negative voltage, so that when the transistor to be recovered is being recovered, it is in a state opposite to its operating state. For example, if the voltage difference between the gate and the substrate is positive when the transistor to be recovered is in the working state, then the voltage difference between the gate and the substrate will be negative during the recovery process; or, if the voltage difference between the gate and the substrate is negative when the transistor to be recovered is in the working state, then the voltage difference between the gate and the substrate will be positive during the recovery process; thus, the transistor is in a completely opposite state between the working state and the recovery process.

[0063] In some embodiments, when the temperature of the transistor to be recovered is higher than a preset temperature, the potentials of the source, drain, and bottom electrodes of the transistor are made the same. For example, the potentials of the source, drain, and bottom electrodes (i.e., the substrate) of the transistor are all 0V; or, for another example, the potentials of the source, drain, and bottom electrodes (i.e., the substrate) of the transistor are all 1V. This disclosure does not limit the specific potential values ​​of the source, drain, and bottom electrodes, as long as the potentials of the three are the same.

[0064] In some embodiments, in order to ensure the recovery effect and extract as many hot electrons as possible from the hot electron accumulation region, it is necessary to control the duration of applying the first voltage to the transistor to be recovered to a preset duration (even if the transistor to be recovered is in a state opposite to the working state and is maintained for the preset duration). The preset duration ranges from (0, 1000], and the unit is seconds.

[0065] In one example, when the transistor to be recovered is a PMOS (P-type field-effect transistor), in the PMOS's operating state, the substrate is grounded at 0V, a negative voltage is applied to the gate, and holes in the channel region concentrate near the gate, allowing the source and drain to conduct under the influence of these holes. When recovering the transistor, a positive voltage is applied to the gate, thereby creating a strong electric field in the substrate opposite to the operating state, causing the transistor to be recovered to be in the opposite state to its operating state.

[0066] In another example, when the transistor to be recovered is an NMOS (N-type field-effect transistor), in the operating state of the NMOS, the substrate is grounded to 0V, a positive voltage is applied to the gate, and electrons in the channel region concentrate near the gate, allowing the source and drain to conduct under the influence of electrons. When recovering the transistor, a negative voltage is applied to the gate, thereby creating a strong electric field in the substrate opposite to the operating state, causing the transistor to be recovered to be in the opposite state to its operating state.

[0067] In this embodiment, the transistor to be restored is subjected to a strong electric field opposite to its operating state, while ensuring that the temperature of the transistor to be restored is higher than a preset temperature, so as to assist in providing energy to the hot electrons, so that the hot electrons are extracted from the hot electron accumulation region, thereby improving the reliability and service life of the semiconductor device.

[0068] According to an exemplary embodiment, such as Figure 3 As shown, the transistor recovery method in this embodiment includes:

[0069] S110. When the temperature of the transistor to be recovered is higher than a preset temperature, a first voltage is applied between the gate and the bottom electrode of the transistor to be recovered. The voltage applied between the gate and the bottom electrode of the transistor to be recovered in the working state is defined as a second voltage, and the first voltage and the second voltage have opposite signs.

[0070] S120. When the temperature of the transistor to be recovered is higher than a preset temperature, a fourth voltage is applied between at least one of the source and drain electrodes of the transistor to be recovered and the bottom electrode.

[0071] In this embodiment, steps S110 and S120 are not limited by a specific order of implementation and can be implemented simultaneously. The implementation method of step S110 is basically the same as that in the above embodiments, except that in some embodiments, the amplitude of the first voltage is 0.3 to 0.6 times the amplitude of the second voltage, so as to provide a sufficiently strong electric field without damaging the transistor due to an excessively large amplitude of the first voltage.

[0072] In step S120, three scenarios may be included during implementation: first, applying a fourth voltage between the source and bottom electrodes of the transistor to be recovered; second, applying a fourth voltage between the drain and bottom electrodes of the transistor to be recovered; and third, applying a fourth voltage between the drain and bottom electrodes of the transistor to be recovered, and between the source and bottom electrodes of the transistor to be recovered, respectively, that is, applying the same voltage to the source and drain.

[0073] In this context, the voltage applied between the source and drain of the transistor to be recovered when it is in operation is defined as the third voltage, and the fourth voltage has the opposite sign to the third voltage. That is, of the third and fourth voltages, one is positive and the other is negative. For example, the amplitude of the fourth voltage is 0.8 to 1.2 times the amplitude of the third voltage.

[0074] In this embodiment, by applying a fourth voltage between at least one of the source and drain electrodes of the transistor to be recovered and the bottom electrode, the electric field strength formed in the substrate is further enhanced, thereby improving the recovery effect of the transistor.

[0075] According to an exemplary embodiment, such as Figure 4 As shown, the transistor recovery method in this embodiment includes the following steps:

[0076] S210. Detect the temperature of the transistor to be restored and determine whether the temperature of the transistor to be restored is higher than the preset temperature;

[0077] If yes, proceed to steps S220 and S230; otherwise, proceed to step S240.

[0078] S220. Apply a first voltage between the gate and bottom electrode of the transistor to be recovered.

[0079] S230, A fourth voltage is applied between at least one of the source and drain electrodes of the transistor to be recovered and the bottom electrode.

[0080] S240. Heat the transistor to be recovered so that the temperature of the transistor to be recovered is higher than the preset temperature.

[0081] After S240 is executed, S220 and S230 will continue to be executed.

[0082] The implementation method of step S220 is the same as that of step S110, and the implementation method of step S230 is the same as that of step S120, so they will not be described again here. Furthermore, steps S220 and S230 do not have a specific execution order and can be executed simultaneously.

[0083] In step S210, when detecting the temperature of the transistor to be restored, a temperature sensor can be used, for example, by placing a temperature sensor near the transistor to be restored for temperature monitoring. The preset temperature involved in this step is the same as the preset temperature to be maintained for the transistor to be restored in step S110, which is 50°C to 150°C.

[0084] In step S240, to ensure the recovery effect of the transistor to be recovered, it needs to be heated. Heating can be achieved, for example, by placing a resistor close to the transistor in the circuit. By supplying power to the resistor, its temperature rises, thereby increasing the temperature near the transistor and heating it. In other words, during the recovery process, if the temperature of the transistor to be recovered is lower than a preset temperature, it is heated to raise its temperature above the preset temperature. If the temperature of the transistor to be recovered is already higher than the preset temperature before the recovery operation, it can be heated to maintain this higher temperature, preventing the transistor's temperature from dropping and ensuring the recovery effect.

[0085] In this embodiment, the transistor to be recovered is detected, and it is determined whether the temperature of the transistor to be recovered is higher than the preset temperature. If the temperature of the transistor to be recovered is lower than the preset temperature, then the transistor to be recovered needs to be heated to ensure that more hot electrons can be extracted from the hot electron accumulation area, thereby improving the recovery effect.

[0086] In some possible embodiments, before performing the transistor recovery method, it is necessary to determine whether the transistor is the one to be recovered. When the transistor is determined to be the one to be recovered, the transistor recovery method described in the above embodiments can be used to recover the transistor.

[0087] In one example, when a semiconductor device includes multiple transistors, the threshold voltage or turn-off leakage current of the transistors is detected. When the threshold voltage exceeds a preset voltage threshold (for example, both exceeding and falling below the preset voltage threshold are abnormal states; NMOS and PMOS are affected differently by the hot carrier injection effect, resulting in different threshold voltage changes), and / or, when the turn-off leakage current is greater than or equal to a preset current threshold, the transistor is determined to be a transistor to be recovered. That is, if either of the above two conditions is met, the transistor can be determined to be a transistor to be recovered.

[0088] When the parameter being detected is a threshold voltage, if the preset threshold is exceeded, it indicates that the transistor has encountered a reliability problem due to reasons such as hot electron-induced penetration or unstable bias temperature. The transistor needs to be restored to ensure it can function normally. The preset voltage threshold can be set to a reference threshold voltage for reliable transistor operation, or a value slightly lower than the reference threshold voltage.

[0089] When the parameter being monitored is the turn-off leakage current, if the turn-off leakage current exceeds a preset current threshold, it indicates that thermionic leakage current or bias temperature instability has occurred, requiring the transistor to be restored to ensure its normal operation. The preset current threshold can be set to the reference turn-off leakage current of a transistor that has not experienced thermionic leakage current, or a value slightly smaller than the reference turn-off leakage current.

[0090] In another example, due to prolonged use, transistors exhibit aging. To ensure the lifespan of semiconductor devices containing transistors, it is necessary to monitor the transistors by tracking their cumulative operating time. When the cumulative operating time is greater than or equal to a preset operating time, it indicates that the transistor may have reached a state where hot electron-induced penetration occurs or bias temperature instability is present. This transistor is then identified as needing restoration. The preset operating time could be, for example, 100 hours. This preset operating time is an empirical value and can be set according to actual needs.

[0091] In this embodiment, the threshold voltage, turn-off leakage current, or cumulative operating time of the transistor can be used to determine whether the transistor is a transistor to be recovered, so as to perform the recovery method on the transistor to be recovered in a timely manner and reduce the turn-off leakage current.

[0092] The method in this embodiment will be described below with reference to a specific application scenario. In an exemplary embodiment, the transistor recovery method is applied in the recovery process after an aging experiment.

[0093] Before leaving the factory, transistors undergo aging tests. During these tests, a high voltage is applied to the drain. Under the influence of a strong electric field, thermionic breakdown occurs, leading to a shortening of the effective channel length and a sharp increase in turn-off leakage current. In one example, using a P-type transistor, the aging conditions are: gate voltage 0V, bottom voltage 0V or less than -0.5V, and the voltage between the drain and source is -1.1Vdd to -1.5Vdd, where Vdd represents the voltage applied between the source and drain under normal operating conditions. The temperature is 90℃ to 150℃, and the time is less than or equal to 1000 seconds. Typically, after the aging test, semiconductor devices (including transistors) are baked at 250–350℃ for one hour. This high-temperature baking has a certain recovery effect on thermionic breakdown. However, as transistor sizes continue to shrink, thermionic breakdown becomes more severe, and baking alone is insufficient to achieve the desired effect. Furthermore, since the aging test equipment cannot be heated to a high temperature of 250-350°C, an additional process station is required when restoring transistors through high-temperature baking, making the process steps cumbersome.

[0094] like Figure 5 The diagram illustrates the relationship between drain current and gate voltage during the recovery process using existing recovery methods. Figure 5 The horizontal axis represents the gate voltage in volts (V), and the vertical axis represents the drain current in amperes (A). Curve L1 shows the relationship between drain current and gate voltage before hot-electron-induced breakdown; curve L2 shows the relationship after aging; and curve L3 shows the relationship after high-temperature baking. Based on... Figure 5 It is known that using existing recovery methods to restore transistors after aging experiments results in a significant difference between the turn-off leakage current when the gate voltage is 0V and the turn-off leakage current when the hot electron breakdown effect has not occurred, indicating poor recovery performance.

[0095] To address the aforementioned issues, the transistor recovery method in this embodiment lowers the baking temperature to 50°C to 150°C. Since the baking temperature in this embodiment is not high, it can be reached on the aging test bench. Therefore, after the aging test, there is no need to transfer the transistor to other process stations for high-temperature baking; baking can be performed on the aging test bench, reducing process steps. After completing the transistor recovery process using the recovery method in this embodiment, the voltage applied to the gate, source, drain, and substrate is disconnected, and the transistor is cooled to room temperature before subsequent testing processes, such as packaging testing, are performed.

[0096] In one example of transistor recovery, the transistor to be recovered is a PMOS. The voltages applied to the drain, source, and substrate are all 0V. The voltage applied to the gate is 0.3 to 0.6 times the amplitude of a second voltage. The baking temperature is 80°C to 150°C, and the recovery time is less than or equal to 1000 seconds. Here, the second voltage is the voltage applied to the gate in the operating state. In this example, the voltage applied to the gate is the first voltage, and the first voltage has the opposite sign to the second voltage.

[0097] In another example, the transistor to be recovered is a PMOS. The voltage applied to the substrate is 0V. The voltage applied to the gate is 0.3 to 0.6 times the amplitude of a second voltage, where the second voltage is the voltage applied to the gate under normal operating conditions. In this example, the voltage applied to the gate is the first voltage, and the first and second voltages have opposite signs. The voltage applied to the drain is 0.8 to 1.2 times the amplitude of a third voltage, and the voltage applied to the source is 0.8 to 1.2 times the amplitude of the third voltage, where the third voltage is the voltage applied between the source and drain under operating conditions. The third voltage has opposite signs to the fourth voltage. The baking temperature is 80°C to 150°C, and the recovery time is less than or equal to 1000 seconds.

[0098] See Figure 6 The diagram illustrates the relationship between drain current and gate voltage during the recovery process using the recovery method described in this disclosure. Figure 6 The horizontal axis represents the gate voltage in volts (V), and the vertical axis represents the drain current in amperes (A). Curve M1 shows the relationship between drain current and gate voltage before hot-electron-induced breakdown; curve M2 shows the relationship between drain current and gate voltage after aging; and curve M3 shows the relationship between drain current and gate voltage after 100 seconds of recovery using the recovery method described in this disclosure. Figure 6 It can be seen that after the recovery process is completed, the turn-off leakage current when the gate voltage is 0V is very close to the turn-off leakage current value when the hot electron breakdown effect has not occurred. The recovery effect is very good, the value of the transistor turn-off leakage current is significantly reduced, and the reliability and stability of the transistor are improved.

[0099] The transistor recovery method described in this embodiment can restore transistor performance by eliminating the hot electron-induced breakdown effect without adding excessive time. Furthermore, it reduces one process station compared to existing recovery methods and can be applied to the recovery process after aging experiments on wafer-level and package-level products.

[0100] In an exemplary embodiment, the transistor recovery method in this embodiment is described using the post-manufacturing use of a semiconductor device as an application scenario. After the transistor leaves the factory, it will exhibit bias temperature instability (BTI) during long-term use. The BTI effect is mainly due to the instability of the Si-H bonds in silicon oxide, causing the transistor to operate under high temperature and high pressure for a long time, resulting in the breakage of the Si-H bond, the ionization of H elements, and thus the drift of the gate voltage. Bias temperature instability includes two types: positive bias temperature instability and negative bias temperature instability. The negative bias temperature instability effect mainly occurs in the inversion state of P-type transistors. Its generation process mainly involves the generation and passivation of positive charges, namely the generation of dangling bonds at the interface and fixed charge in the oxide layer, as well as the overgeneration and diffusion of substances (hydrogen and water vapor are the two main substances causing NBTI), which increases the device threshold voltage. As the transistor is used for longer periods, its performance will degrade. The positive bias temperature instability effect has a significant impact on N-type transistors. However, regardless of whether the transistor exhibits positive or negative bias temperature instability, the transistor recovery method disclosed in this invention can be used to recover the transistor (for example, by applying a first voltage between the gate and bottom electrode of the transistor to be recovered when the temperature of the transistor to be recovered is higher than a preset temperature). Simultaneously, the transistor recovery method disclosed in this invention can also be used to recover from the transistor reliability degradation caused by the hot carrier injection (HCI) effect.

[0101] When a transistor's threshold voltage exceeds a preset voltage threshold, or its turn-off leakage current is greater than or equal to a preset current threshold, or its cumulative operating time is greater than or equal to a preset operating time, the transistor can be identified as a transistor requiring recovery, i.e., a transistor to be recovered. Once a transistor is identified as a transistor to be recovered, its temperature is detected. If the temperature is higher than a preset temperature, the transistor can be directly recovered. If the temperature is lower than the preset temperature, the transistor needs to be heated before voltages can be applied to the gate, source, and drain for recovery. For example, if the transistor to be recovered is a PMOS, the voltage applied to the substrate is 0V, the voltage applied to the gate is a second voltage value with an amplitude of 0.3 to 0.6 times the second voltage value, the voltage applied to the drain is a third voltage value with an amplitude of 0.8 to 1.2 times the third voltage value, the voltage applied to the source is a third voltage value with an amplitude of 0.8 to 1.2 times the third voltage value, the baking temperature is 80°C to 150°C, and the recovery time is less than or equal to 1000 seconds. The second voltage value is the voltage amplitude applied to the gate under normal operating conditions; the third voltage value is the voltage amplitude applied between the source and drain under normal operating conditions. See also Figure 8 As shown, the strong electric field formed between the source S and the drain D will extract the hot electrons that accumulate near the top edge of the shallow trench isolation structure near the gate G and enter the interface between the nitride layer and the oxide layer, thereby increasing the effective channel length.

[0102] See Figure 7 This diagram illustrates the relationship between drain current and gate voltage during the recovery process using the recovery method described in this disclosure. Curve N1 represents the relationship between drain current and gate voltage before hot-electron-induced breakdown; curve N2 represents the relationship between drain current and gate voltage after applying voltage to the four-terminal device after prolonged operation; curve N3 represents the relationship between drain current and gate voltage after 10 seconds of recovery; N4 represents the relationship between drain current and gate voltage after 100 seconds of recovery; N5 represents the relationship between drain current and gate voltage after 200 seconds of recovery; N6 represents the relationship between drain current and gate voltage after 500 seconds of recovery; and N7 represents the relationship between drain current and gate voltage after 1000 seconds of recovery. Figure 7 As shown in the curves, the threshold voltage gradually increases with the increase of the recovery process time (in the direction indicated by arrow A in the figure), which means that the number of accumulated hot electrons gradually decreases and the transistor is gradually recovered. When the transistor is recovered using the transistor recovery method of this disclosure, when the recovery time lasts for 1000 seconds, the difference between the turn-off leakage current when the gate voltage is 0V and the turn-off leakage current when no hot electron breakdown effect occurs is small, indicating a good recovery effect.

[0103] In an exemplary embodiment of this disclosure, when the temperature of the transistor to be restored is higher than a preset temperature, a first voltage opposite to that in the operating state is applied between the gate and the bottom electrode to put the transistor to be restored in a bias state opposite to the operating state, thereby weakening or eliminating the hot electron-induced breakdown effect. This transistor restoration method can be conveniently executed not only during aging tests but also during transistor use.

[0104] In an exemplary embodiment of this disclosure, a semiconductor device is provided. Figure 9 This is a schematic diagram of a semiconductor device according to an exemplary embodiment, such as... Figure 9 As shown, the semiconductor device includes a transistor 901 and a recovery circuit 902, with the recovery circuit 902 coupled to the transistor 901. The recovery circuit 902 is configured to apply a first voltage between the gate and bottom electrode of the transistor to be recovered when the transistor is the transistor to be recovered and the temperature of the transistor to be recovered is higher than a preset temperature. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage, and the first voltage and the second voltage have opposite signs, so that the transistor to be recovered is in a state opposite to its operating state. In implementation, the recovery circuit can be, for example, a switching circuit electrically connected to the gate of the transistor. Conditions are set for the switching circuit to apply the first voltage between the gate and bottom electrode when the transistor is the transistor to be recovered, so that the transistor to be recovered is in a bias state opposite to its operating state. When the transistor is in the operating state, the switching circuit is turned off, thus not affecting the normal operation of the transistor. The recovery circuit 902 can refer to common switching circuits, and will not be described in detail here.

[0105] According to some embodiments of this disclosure, the semiconductor device further includes a temperature sensing circuit 905, which is configured to detect the temperature of the transistor to be recovered and determine whether the temperature of the transistor to be recovered is higher than a preset temperature. The temperature sensing circuit 905 may be a circuit structure that includes a temperature sensor, and can refer to common temperature sensing circuits, which will not be described in detail here.

[0106] According to some embodiments of this disclosure, a semiconductor device includes a detection circuit 906. The detection circuit 906 is configured to detect a threshold voltage or a turn-off leakage current of a transistor to determine whether the transistor is a transistor to be recovered; and / or, the detection circuit 906 is configured to detect the cumulative operating time of the transistor to determine whether the transistor is a transistor to be recovered. When the detection circuit 906 is configured to detect the threshold voltage or the turn-off leakage current of the transistor, the detection circuit 906 can be a circuit structure including a voltage detection unit or a current detection unit. When the detection circuit 906 is configured to detect the cumulative operating time of the transistor, the detection circuit 906 can be a circuit structure including a timer. The detection circuit 906 can refer to common threshold detection circuits, leakage current detection circuits, or timer circuits, etc., and will not be described in detail here.

[0107] According to some embodiments of this disclosure, the semiconductor device further includes a heating circuit 903 configured to heat the transistor to be recovered so that the temperature of the recovered transistor is higher than a preset temperature. The heating circuit 903 may be a circuit structure including a heating resistor.

[0108] According to some embodiments of this disclosure, the semiconductor device further includes a timing circuit 904 configured to control the duration for which a first voltage is applied to the transistor to be recovered (i.e., the duration for which the transistor to be recovered is in a bias state opposite to its operating state). The timing circuit 904 may be a circuit structure that includes a timer.

[0109] During use, the semiconductor device disclosed herein can automatically detect the state of the transistor. When the transistor needs to be restored, it can automatically use the transistor restoration method in the above method embodiments to restore the transistor to be restored. This can effectively reduce the impact of hot electron-induced breakdown on the transistor, reduce turn-off leakage current, extend the service life of the transistor, and enhance the reliability and stability of the transistor.

[0110] The specific methods by which the various structures in the aforementioned semiconductor device perform operations have been described in detail in the embodiments of the method, and will not be elaborated upon here.

[0111] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, apparatus (devices), or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. Computer storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data), including but not limited to RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible by a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and can include any information delivery medium.

[0112] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0113] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0114] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0115] In this disclosure, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising…” does not exclude the presence of additional identical elements in the article or device that includes said element.

[0116] Although preferred embodiments of the present disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0117] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, the intent of this disclosure also includes these modifications and variations.

Claims

1. A method for recovering a transistor, characterized in that, The recovery method includes: When the temperature of the transistor to be recovered is higher than a preset temperature, a first voltage is applied between the gate and bottom electrode of the transistor to be recovered. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage, and the first voltage has the opposite sign to the second voltage.

2. The transistor recovery method according to claim 1, characterized in that, The amplitude of the first voltage is 0.3 to 0.6 times the amplitude of the second voltage.

3. The transistor recovery method according to claim 1, characterized in that, The recovery method includes: When the temperature of the transistor to be recovered is higher than the preset temperature, the potentials of the source, drain, and bottom electrodes of the transistor to be recovered are made the same.

4. The transistor recovery method according to claim 1, characterized in that, The recovery method includes: When the transistor to be recovered is in the working state, the voltage applied between the source and drain of the transistor to be recovered is a third voltage; The recovery method further includes: When the temperature of the transistor to be recovered is higher than the preset temperature, a fourth voltage is applied between at least one of the source and drain of the transistor to be recovered and the bottom electrode. The amplitude of the fourth voltage is 0.8 to 1.2 times the amplitude of the third voltage, and the fourth voltage has the opposite sign to the third voltage.

5. The transistor recovery method according to claim 1, characterized in that, The recovery method further includes: The duration for which the first voltage is applied to the transistor to be recovered is controlled to be a preset duration; The preset duration ranges from (0, 1000) and is measured in seconds.

6. The transistor recovery method according to claim 1, characterized in that, The preset temperature range is [50, 150], and the unit is degrees Celsius.

7. The transistor recovery method according to claim 1, characterized in that, The recovery method further includes: The temperature of the transistor to be restored is detected, and it is determined whether the temperature of the transistor to be restored is higher than the preset temperature; If so, apply the first voltage between the gate and bottom electrode of the transistor to be recovered; If not, the transistor to be restored is heated so that its temperature is higher than the preset temperature.

8. The transistor recovery method according to claim 1, characterized in that, The recovery method further includes: The threshold voltage of the detected transistor is determined to be the transistor to be recovered when the threshold voltage exceeds a preset voltage threshold; and / or, The turn-off leakage current of the transistor is detected. When the turn-off leakage current is greater than or equal to a preset current threshold, the transistor is determined to be the transistor to be recovered.

9. The transistor recovery method according to claim 1, characterized in that, The recovery method further includes: The cumulative operating time of the transistor is detected. When the cumulative operating time is greater than or equal to a preset operating time, the transistor is determined to be the transistor to be recovered.

10. The transistor recovery method according to claim 1, characterized in that, The transistor is a metal-oxide-semiconductor field-effect transistor.

11. A semiconductor device, comprising: transistor; A recovery circuit, coupled to the transistor, is configured to apply a first voltage between the gate and bottom electrode of the transistor to be recovered when the transistor is a transistor to be recovered and the temperature of the transistor to be recovered is higher than a preset temperature. The voltage applied between the gate and bottom electrode of the transistor to be recovered in the operating state is defined as a second voltage, and the first voltage has the opposite sign to the second voltage.

12. The semiconductor device according to claim 11, characterized in that, The semiconductor device further includes: A temperature sensing circuit is configured to detect the temperature of the transistor to be recovered and determine whether the temperature of the transistor to be recovered is higher than the preset temperature.

13. The semiconductor device according to claim 11, characterized in that, The semiconductor device includes a detection circuit configured to detect a threshold voltage and / or a turn-off leakage current of the transistor to determine whether the transistor is the transistor to be recovered. And / or, The detection circuit is configured to detect the cumulative operating time of the transistor to determine whether the transistor is the transistor to be recovered.

14. The semiconductor device according to claim 11, characterized in that, The semiconductor device further includes: A heating circuit is configured to heat the transistor to be restored such that the temperature of the transistor to be restored is higher than the preset temperature, and / or to maintain the temperature of the transistor to be restored above the preset temperature.

15. The semiconductor device according to claim 11, characterized in that, The semiconductor device further includes: A timing circuit is configured to control the duration for which the first voltage is applied to the transistor to be restored.

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