A dual-laser time-delay synergistic effect simulation system and a semiconductor device characterization method

Abstract

The application discloses a kind of double laser time delay synergistic effect simulation system and semiconductor device characterization method, including double pulse time delay generating unit, for generating two pulse lasers with set relative time delay;Combining focusing incidence unit, for the two lasers are combined and focused to device same target in space;Sampling calibration unit, for sampling from optical path and forming calibration signal;Signal processing measurement unit, for the relative time delay of setting is calibrated according to two-way calibration signal, and device transient electrical response data is collected.The method includes single-beam baseline measurement, time delay online calibration and correction, double-beam time delay scanning and synergistic effect determination.The application realizes the quantitative identification of the time window of semiconductor device synergistic enhancement or mutual inhibition by the time-domain controllable mechanism of double laser independent triggering and non-simultaneous arrival and the online calibration technology of sample surface, significantly improves the accuracy, reproducibility and engineering applicability of radiation simulation.

Description

Technical Field

[0001] This invention relates to the field of ground simulation testing technology for radiation resistance and single-event effect (SEE) of microelectronic devices, and more specifically, to a dual-laser time delay synergistic effect simulation system and a semiconductor device characterization method. Background Technology

[0002] In real space radiation environments, individual devices often exhibit time-dependent coupling responses under the influence of non-simultaneous ionization events. The charge carriers, trap occupancy, and local field distortion excited within the device by the previous event will change the sensitization threshold and current waveform of the subsequent event within a short recovery time, thereby causing the total response to deviate from linear superposition, i.e., a time delay synergistic effect occurs.

[0003] In existing ground-based alternative tests, the pulsed laser single-event effect (PL-SEE) method is widely used by numerous institutions in Europe, America, and China for sensitive element localization and transient equivalence studies due to its spatial resolution and repeatability. For example, the U.S. Naval Research Laboratory (NRL) has been operating a PL-SEE test platform for a long time and has been conducting comparative studies on single-photon / two-photon induced transients of wide-bandgap devices such as GaN and SiC. NRL and NASA's Electronic Devices and Packaging Program (NASA / NEPP) have also published PL-SEE technical guidelines for engineering test planning, providing recommended test ranges and usage conditions for parameters such as wavelength, pulse width, repetition rate, and numerical aperture. In Europe, the European Space Agency / European Space Research and Technology Centre (ESA / ESTEC) has published "Guidelines for SEE Testing with Laser Beams" and is promoting the use of two-photon absorption-transient current technology (TPA-TCT) for bulk carrier injection and transient readout of silicon detectors on platforms such as CERN and TUDORTMund. On the industry side, Northrop Grumman and others have also built PL-SEE facilities and publicly presented their equipment and test results at conferences such as the National Conference on Radiation Effects in Space (NSREC) and the Redundant Data Workshop on Radiation Effects (REDW). Domestically, institutions such as the National Space Science Center of the Chinese Academy of Sciences, the University of Electronic Science and Technology of China, and the China Academy of Engineering Physics have conducted research on laser single-particle induced transients and flips, burn-out screening, and layout-sensitive area mapping for devices using different processes, achieving significant progress in testing methods and mechanism analysis.

[0004] Current research on single-event effects largely focuses on single-pulse studies, with relatively few theoretical and experimental studies on the impact of the sequential arrival of two events on devices, and a lack of device-level schemes that can be repeatedly verified. Based on existing research on dual-pulse lasers, the carrier transport, energy exchange, and thermalization processes of the material evolve over time after the first pulse. When the arrival interval of the second pulse falls within the time window before the device has recovered, the second deposition may superimpose or interfere with the previous process, often resulting in enhancement or suppression. Therefore, it is necessary to set the scanning window according to the actual recovery process of the device under test and obtain an effective time delay through sample surface calibration.

[0005] Multiple experimental results indicate that the sensitivity and response rate of a device change under conditions of total dose (TID) or displacement damage (DDD). Specifically, TID leads to increased charge accumulation within the device and increased defects in interfaces and materials, thereby increasing the probability of device-triggered failure. These changes mean that the effects of the first event last longer, reducing the energy required to trigger the second event, thus increasing the likelihood of the two events superimposed within the device recovery window. Simultaneously, DDD affects carrier transport and recombination, further increasing the probability of triggering errors. Therefore, performing dual-pulse time-delay scanning under low-dose-rate x / γ or displacement damage conditions helps to observe the cooperative response patterns under different recovery states.

[0006] Meanwhile, research revealed that the output of a single mode-locked or gain-switched laser is typically a fixed-period pulse train. External triggers or pulse selectors can only select pulses at integer multiples of the period, making it difficult to achieve two pulses with arbitrarily fine intervals. While splitting a beam into two paths and adding optical path lengths can construct a fixed delay, scanning the relative time delay requires repeatedly moving the optical path, which is slow, prone to drift, and the two energy paths can interfere with each other. Under the same wavelength conditions, interference fringes may also appear, disturbing the actual energy distribution within the device. Therefore, the experiment requires a platform that can scan over a wide time range, is reproducible, and allows for real-time confirmation of the effective time delay on the sample surface. Summary of the Invention

[0007] To address the problems of existing single-pulse laser schemes being unable to simulate non-simultaneous ionization events, the difficulty in stepping and adjusting the time delay of dual pulses, and the lack of online calibration capability for sample surfaces, this invention provides a dual-laser time delay synergistic effect simulation system and a semiconductor device characterization method. By building a system platform, dual-pulse lasers generate two controllable time intervals of ionization deposition in the sensitive area of ​​semiconductor devices, achieving time delay scanning and synergistic window quantization identification in the nanosecond to microsecond range.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A dual-laser time-delay synergistic effect simulation system includes:

[0010] A dual-pulse delay generation unit is used to generate two pulsed laser beams with a set relative time delay;

[0011] The beam combining and focusing incident unit is used to combine the two pulsed laser beams in space and focus them onto the same target point of the semiconductor device sample under test.

[0012] The sampling calibration unit is used to sample from the combined optical path to form a calibration signal corresponding to the arrival time of the two pulsed lasers at the sample surface of the semiconductor device under test and to monitor the laser energy.

[0013] The signal processing and measurement unit is used to receive and process the calibration signal to calibrate the set relative time delay, and to acquire and record the transient electrical response data of the semiconductor device sample under test under laser irradiation.

[0014] The relative delay is adjustable in preset steps within a preset delay window; the signal processing and measurement unit determines the measured delay of the two pulsed laser beams as the effective delay of each scanning point based on the two received calibration signals, and compensates and corrects the set value of the relative delay according to the calibration relationship between the set relative delay and the measured delay; the two pulsed laser beams form a non-simultaneous double-pulse ionization field in the working area of ​​the semiconductor device sample under test to characterize the time synergy effect.

[0015] Specifically, the dual-pulse delay generation unit includes two independent pulsed lasers and electronic delay units electrically connected to the two pulsed lasers respectively. The electronic delay units are used to provide trigger signals to the pulsed lasers and to set and adjust the relative delay.

[0016] Specifically, the pulsed laser is configured with a wavelength of 355 nm, 532 nm, or 1064 nm or its equivalent wavelength, with a pulse width of 0.1–10 ns, and is capable of outputting in either a single-trigger mode or a repetitive-trigger mode. Single-event effect characterization of the device preferably employs a single-trigger or low-repetition-rate trigger mode to avoid heat accumulation; the high-frequency repetitive-trigger mode is mainly used for dynamic response verification of the signal processing measurement unit.

[0017] Specifically, the beam combining and focusing incident unit includes an orthogonal beam combiner, a main optical path, and an objective lens connected in sequence. The orthogonal beam combiner is used to spatially combine two pulsed laser beams, the main optical path is used to transmit the combined laser beam to the objective lens, and the objective lens is used to focus the combined laser beam onto the same target point of the semiconductor device sample under test. The focal spot diameter is 10–50 μm, and the spatial confocal error is controlled within 1 µm.

[0018] Specifically, the sampling calibration unit includes a sampling plate, a beam splitter, an energy meter, a beam splitter, a first photodetector, and a second photodetector. The sampling plate is disposed in the optical path after beam combining and is used to split the sampling beam according to a set ratio. The beam splitter is used to split the sampling beam into two paths, one of which is incident on the energy meter to monitor the pulse energy, and the other is incident on the beam splitter. The beam splitter is used to separate the combined sampling beam into two sub-beams corresponding to the original two pulsed laser beams, and respectively incident on the first photodetector and the second photodetector to form calibration signals.

[0019] Specifically, the signal processing measurement unit includes an oscilloscope, and a first transimpedance amplifier, a second transimpedance amplifier, and a third transimpedance amplifier connected to the oscilloscope. The first transimpedance amplifier is connected to the semiconductor device sample under test and is used to convert the transient current signal generated by the device under laser irradiation into a voltage signal and amplify it. The second and third transimpedance amplifiers are connected to a first photodetector and a second photodetector, respectively, and are used to amplify the calibration signal. The oscilloscope is used to receive the signal from the first transimpedance amplifier to record the transient electrical response data of the device, and simultaneously receive the two calibration signals output by the second and third transimpedance amplifiers. The difference in the arrival time of the leading edges of the two calibration signals is determined as the measured time delay.

[0020] Specifically, the oscilloscope has a sampling rate of not less than 10 GSa / s and an analog bandwidth of not less than 1 GHz; the bandwidths of the first transimpedance amplifier, the second transimpedance amplifier, and the third transimpedance amplifier are all not less than 1 GHz.

[0021] Furthermore, the present invention also provides a semiconductor characterization method using the above-described dual-laser time delay synergy simulation system, comprising the following steps:

[0022] S1. Single-beam baseline measurement: Obtain the reference response characteristics of the semiconductor device sample under test when two pulsed lasers act alone;

[0023] S2. Online time delay calibration and correction: Set the target time delay, collect two calibration signals corresponding to two pulsed lasers, obtain the measured time delay based on the difference in arrival times of the leading edges of the two calibration signals, and establish the calibration relationship between the set time delay and the measured time delay.

[0024] S3, Dual-beam delay scanning: Scanning is performed within the preset delay window according to the relative delay set in steps. At each scanning point, the measured delay is used as the effective delay, and the transient electrical response data of the device is collected synchronously.

[0025] S4. Synergistic Effect Determination: At each effective delay point, extract the double-pulse response characteristic quantity of the semiconductor device sample under test under the synergistic effect of the double pulse, and compare it with the reference response characteristic quantity under the same energy conditions; when the deviation of the double-pulse response characteristic quantity relative to the reference response characteristic quantity exceeds the preset determination threshold, it is determined that there is a synergistic effect at the effective delay point, and the time window of the synergistic effect is determined according to the effective delay range that continuously meets the determination conditions; wherein, the synergistic effect includes synergistic enhancement and synergistic suppression, which are determined according to the direction of the response deviation.

[0026] Specifically, the preset time delay window is determined based on the recovery time of the single-pulse transient response of the semiconductor device under test. During step scanning, a coarse scan is first performed within the preset time delay window using a first time delay step. The candidate synergistic effect time domain interval is determined based on the change of the dual-pulse response characteristic quantity with the effective time delay. Then, a fine scan is performed within the candidate synergistic effect time domain interval using a second time delay step smaller than the first time delay step, so as to determine the boundary of the synergistic effect time window and its change characteristics.

[0027] Specifically, the dual-pulse response characteristics include at least one of the following: event trigger probability, transient current peak value, pulse width, integrated charge, and threshold energy.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) This invention uses two independent pulsed lasers and an electronic delay unit to work together to set a relative delay within a preset delay window and scan in steps. Combined with the measured delay calibration at the sample surface, it overcomes the problem that the adjustment range of fixed delay formed by single laser beam splitting or pulse selection to form an integer multiple of the repetition period is limited, making it possible to systematically study the time-coordinated response of semiconductor devices on the nanosecond to microsecond scale.

[0030] (2) Through a specially configured sampling calibration unit and signal processing measurement unit, this invention can directly measure the actual arrival time difference of two pulsed lasers near the sample surface in real time during the experiment, and correct the preset time delay. This effectively eliminates the time delay uncertainty caused by electronic delayer error, optical path length difference, and system timing jitter. At the same time, it establishes and applies the calibration relationship between the set time delay and the measured time delay, ensuring the accuracy and traceability of the time delay parameters in each experiment. This solves the core problem of poor reproducibility of experimental results and difficulty in comparing data from different platforms caused by inaccurate time delay in previous methods.

[0031] (3) The present invention uses a transimpedance amplifier with a bandwidth of not less than 1 GHz and an oscilloscope with a sampling rate of not less than 10 GSa / s and an analog bandwidth of not less than 1 GHz to form a measurement link. It can record the nanosecond-level transient current or voltage response of semiconductor devices under the synergistic effect of dual pulses within the system bandwidth range, and extract response characteristics such as event trigger probability, single-particle transient peak value, pulse width, integrated charge, and threshold energy to quantify the strength and time window of the synergistic effect.

[0032] (4) By designing an adjustable time delay and an independently adjustable energy ratio of two laser beams, and combining an adjustable incident angle and micro-focal spot focusing, this invention can flexibly simulate a variety of complex dual-event incident scenarios in the space radiation environment. This invention can not only be used for screening and evaluating the device's ability to resist synergistic effects, but also, through systematic parameter scanning, quantitatively reveal the influence of parameters such as time delay and energy ratio on synergistic effects (enhancement or suppression), providing reliable experimental data support for a deeper understanding of its physical mechanism and the establishment of hardening design criteria. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of an embodiment of the present invention.

[0034] Figure 2 The voltage response curves for single-trigger mode and repeated-trigger mode under 0.6 MHz operating conditions in an embodiment of the present invention are shown.

[0035] Figure 3 The figures show the current response curves for single-trigger mode and repeated-trigger mode under 6.7 MHz operating conditions in an embodiment of the present invention.

[0036] Figure 4 The figures show the finite element simulation curves of the terminal current response under different relative time delays in an embodiment of the present invention.

[0037] In the above figures, the component names corresponding to the reference numerals are as follows:

[0038] 1-Pulsed laser, 2-Electronic delay unit, 3-Orthogonal beam combiner, 4-Main optical path, 5-Objective lens, 6-Sampling plate, 7-Beam splitter, 8-Energy meter, 9-Band demultiplexer, 10-First photodetector, 11-Second photodetector, 12-Oscilloscope, 13-First transimpedance amplifier, 14-Second transimpedance amplifier, 15-Third transimpedance amplifier, 16-Sample / probe stage. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0040] Example

[0041] like Figure 1 As shown, this dual-laser time-delay synergy simulation system generates two pulsed laser beams with precise and controllable relative time delays, and confocalizes them onto the same sensitive point of a semiconductor device. Combined with online time-delay calibration and high-fidelity measurement, it achieves quantitative characterization of the single-particle time synergy effect. The system specifically comprises four main parts: a dual-pulse time-delay generation unit, a beam combining and focusing incident unit, a sampling calibration unit, and a signal processing and measurement unit. Control and safety systems can also be configured simultaneously.

[0042] The dual-pulse delay generation unit is used to generate two pulsed laser beams with a set relative delay to simulate the synergistic effect caused by incident at different times. The dual-pulse delay generation unit includes two independently triggerable pulsed lasers 1, and electronic delay units 2 electrically connected to each of the two pulsed lasers. The electronic delay units provide trigger signals to the pulsed lasers and set and adjust the relative delay; the relative delay is adjustable in preset steps within a preset delay window. The lower limit of the preset delay window corresponds to the state where the two pulsed laser beams arrive approximately simultaneously, and its upper limit is determined based on the recovery time of the single-pulse transient response of the semiconductor device under test. In this embodiment, the example delay window is 0–10 μs. The wavelength of the pulsed lasers can be selected from 355 nm, 532 nm, 1064 nm, or their equivalent wavelengths to adapt to the absorption characteristics of different semiconductor materials. The output pulse width can be adjusted within the range of 0.1–10 ns and can be output in single-trigger mode or repeated-trigger mode. For single-event effect characterization of the device, a single-shot or low-repetition-rate triggering mode is preferred to avoid heat accumulation. High-frequency repetitive triggering modes are mainly used for dynamic response verification of the signal processing measurement unit. The energy of the two pulsed laser beams is independently adjusted by setting the laser power to obtain the target energy ratio E2 / E1.

[0043] The beam combining and focusing incident unit is used to spatially combine the two pulsed laser beams and focus them onto the same target point of the semiconductor device sample under test. The beam combining and focusing incident unit includes an orthogonal beam combiner 3, a main optical path 4, and an objective lens 5 connected in sequence. The orthogonal beam combiner spatially combines the two pulsed laser beams and can be a polarizing beam splitter (PBS). The two pulsed laser beams are respectively adjusted to be linearly polarized light (e.g., P-beam and S-beam) and incident at a specific angle. The polarizing beam splitter efficiently combines these two orthogonally polarized laser beams into a single collinear propagating combined laser beam. The main optical path transmits the combined laser beam to the objective lens. The objective lens is used to focus the combined laser beam onto the same target point of the semiconductor device sample under test. A long working distance objective lens can be used, with the spatial confocal error controlled within 1 µm. The focal spot diameter is preferably 10–50 μm, matching the sensitive area of ​​the device. The semiconductor device sample under test is mounted on a sample / probe stage 16 with X / Y translation and small-angle pitch adjustment capabilities to ensure that the laser is confocal to the same point and the incident direction can be finely adjusted as needed.

[0044] The sampling calibration unit is used to sample from the combined optical path to form a calibration signal corresponding to the arrival time of the two pulsed laser beams at the sample surface of the semiconductor device under test, and to monitor the laser energy. The sampling calibration unit includes a sampling plate 6, a beam splitter 7, an energy meter 8, a beam deflector 9, a first photodetector 10, and a second photodetector 11. The sampling plate is positioned in the combined optical path (i.e., the main optical path) to split the sample beam at a set ratio, typically 1% to 5%, preferably 1%. The vast majority of the remaining light continues to propagate along the main optical path to the sample, thus having minimal impact on the laser energy acting on the sample. The beam splitter can be a 50:50 beam splitter, used to split the sample beam into two paths: one path is incident on the energy meter to monitor the pulse energy, providing data for confirming the energy ratio E2 / E1 and determining drift; the other path is incident on the beam deflector. The beam splitter corresponds functionally to the beam combiner and can also be a polarizing beam splitter prism. It is used to separate the sampled beam of the combined beam into two sub-beams corresponding to the original two pulsed laser beams, and respectively incident on the first photodetector and the second photodetector. The two photodetectors convert the optical pulse signal into the corresponding electrical pulse signal, and their output is a calibration signal reflecting the arrival time and intensity of the original two pulsed laser beams.

[0045] The signal processing and measurement unit is used to receive and process the calibration signal to calibrate the set relative time delay, and to acquire and record the transient electrical response data of the semiconductor device sample under test under laser irradiation (including dual-pulse synergy). The signal processing and measurement unit includes an oscilloscope 12, and a first transimpedance amplifier 13, a second transimpedance amplifier 14, and a third transimpedance amplifier 15, each connected to the oscilloscope. The first transimpedance amplifier is connected to the output pin of the semiconductor device sample under test and is used to convert the transient current signal generated by the device under laser irradiation into a voltage signal and amplify it to record nanosecond-level single-particle transient waveforms. The second and third transimpedance amplifiers are connected to a first photodetector and a second photodetector, respectively, to amplify the calibration signal. The bandwidths of the first, second, and third transimpedance amplifiers are all not less than 1 GHz to meet the recording requirements of nanosecond-level pulse signals. The oscilloscope can be configured as a multi-channel high-speed digital oscilloscope with a sampling rate of not less than 10 GSa / s and an analog bandwidth of not less than 1 GHz. Its CH1 channel is used to receive the signal from the first transimpedance amplifier to record the transient electrical response data of the device. Its CH2 and CH3 channels are used to receive the two calibration signals output from the second and third transimpedance amplifiers. The difference in arrival time of the leading edges of the two calibration signals is determined as the measured time delay. Before the test, a calibration relationship between the set time delay and the measured time delay can be established at several set points. During the test, the measured time delay is used as the effective time delay, and the set value of the relative time delay is compensated and corrected according to the aforementioned calibration relationship. Two pulsed laser beams form a non-simultaneously arriving double-pulse ionization field in the working area of ​​the semiconductor device sample under test to characterize the time synergy effect. The energy measurement is completed on the sampling branch without affecting the main optical path, and E1, E2, and E2 / E1 can be obtained. The system records and extracts response characteristic indicators such as threshold energy, event trigger probability, transient current peak value, pulse width, and integrated charge. When the dual-pulse measurement indicators deviate significantly from the single-beam baseline measurement indicators within a certain relative time delay segment, it is determined that a synergistic effect window exists.

[0046] In terms of control and safety systems, devices such as mechanical shutters, emergency stop switches, goggles and light shields, power-on interlocks, and overcurrent limiting can be configured to achieve functions such as device protection, interlocking, and one-button operation. For example, light shields can be installed in the laser path and sample area for protection, and laser operation should be carried out in accordance with relevant safety regulations.

[0047] This embodiment also provides a semiconductor characterization method using the above-described dual-laser time delay synergy simulation system, which can be used to evaluate the single-event flip (SEU) time synergy effect of SRAM devices, including the following steps:

[0048] S1. Single-beam baseline measurement: The baseline response characteristics of the semiconductor device sample under test are acquired when each of the two pulsed laser beams acts independently, including at least one of the following: event trigger probability, transient current peak, pulse width, integrated charge, and threshold energy. Taking threshold energy as an example, only the first pulsed laser is turned on, and the laser focus is aligned with the same sensitive cell in the SRAM array. Multiple irradiations are performed at each energy point, and the number of bit flips is recorded by the external test circuit. The incident energy corresponding to an event trigger probability of 50% is taken as the single-beam threshold energy of the first pulsed laser. Following the same sample position, bias state, and judgment method, only the second pulsed laser is turned on to obtain the single-beam threshold energy of the second pulsed laser.

[0049] S2. Online Delay Calibration and Correction: A target delay is set, and two calibration signals corresponding to the two pulsed laser beams are acquired through the signal processing and measurement unit. The measured delay is obtained based on the difference in arrival times of the leading edges of the two calibration signals, and a calibration relationship is established between the set delay and the measured delay. Specifically, pulsed lasers one and two are simultaneously activated, and the target relative delay of the electronic delay unit is set through the system control software. For each set delay, the system triggers a dual-pulse emission, and the oscilloscope automatically captures the waveforms of channels CH2 and CH3, calculating the corresponding measured delay. After traversing all set points, the system automatically generates and stores a "Set Delay - Measured Delay" calibration table. This calibration table reflects the system's inherent delay deviation and jitter range. In subsequent formal testing, the measured delay obtained by the oscilloscope will be used as the effective delay value, thus achieving online correction of the relative delay.

[0050] S3. Dual-beam delay scanning: Scanning is performed within a preset delay window using a step-adjusted relative delay. The measured delay at each scanning point is used as the effective delay, and transient electrical response data of the device is acquired synchronously. Multiple repeated measurements are typically performed during data acquisition. The preset delay window is determined based on the recovery time of the single-pulse transient response of the semiconductor device under test. Its lower limit corresponds to the state where two pulsed laser beams arrive approximately simultaneously, and its upper limit is determined based on the recovery time of the single-pulse transient response of the semiconductor device under test, for example, in the range of 0–10 µs. During step scanning, a coarse scan is first performed within the preset delay window using a first delay step. The candidate synergistic effect time domain interval is determined based on the change of dual-pulse response characteristic quantities with the effective delay. Then, a fine scan is performed within the candidate synergistic effect time domain interval using a second delay step smaller than the first delay step to determine the boundary of the synergistic effect time window and its changing characteristics. During the test, the sample position, device bias, trigger reference, and energy calibration method are kept consistent.

[0051] S4. Synergistic Effect Determination: At each effective delay point, the dual-pulse response characteristic quantity of the semiconductor device sample under test under dual-pulse synergistic effect is extracted and compared with the reference response characteristic quantity under the same energy condition. When the deviation of the dual-pulse response characteristic quantity relative to the reference response characteristic quantity exceeds a preset determination threshold, a synergistic effect is determined to exist at that effective delay point, and the time window of the synergistic effect is determined according to the effective delay range that continuously meets the determination condition. The synergistic effect includes synergistic enhancement and synergistic suppression, determined according to the direction of the response deviation. For example, a positive deviation indicates synergistic enhancement, and a negative deviation indicates synergistic suppression. The dual-pulse response characteristic quantity includes at least one of event trigger probability, transient current peak value, pulse width, integrated charge, and threshold energy. For the peak value, integrated charge, or event trigger probability index, a dual-pulse response characteristic quantity higher than the reference response characteristic quantity can be determined as synergistic enhancement, and a value lower than the reference response characteristic quantity can be determined as synergistic suppression. For the threshold energy index, a dual-pulse threshold energy lower than the reference threshold energy indicates synergistic enhancement, and a value higher than the reference threshold energy indicates synergistic suppression.

[0052] To verify the system's dynamic response capability under different repetitive triggering cycles, 0.6 MHz and 6.7 MHz were selected as two verification conditions, with a single trigger waveform used as a control for each condition. The repetitive triggering cycles corresponding to 0.6 MHz and 6.7 MHz are approximately 1.67 μs and 149 ns, respectively, used to verify the waveform resolution and recovery capabilities of the measurement link at microsecond and nanosecond pulse intervals. Figure 2 The time-voltage response curves shown, under 0.6 MHz operating conditions, exhibit a single-trigger mode peak value of approximately 1.55 V, approaching the baseline after about 2.7 μs; the repetitive-trigger mode response peak is located at approximately 1.43 μs, with a peak value of approximately 2.9 V, and a tailing effect lasting until approximately 7.8 μs. Figure 3 The time-current response curves shown indicate that, under 6.7 MHz operating conditions, the peak values ​​for both modes are approximately 56 mA. In the single-trigger mode, approximately 10–15 mA of current remains after 0.5 μs, and a residual current of approximately 2 mA persists near 2.0 μs. In the repeated-trigger mode, the current returns to the baseline relatively quickly after the peak. These results demonstrate that the measurement link of this invention can distinguish peak values, recovery processes, and tailing characteristics at different trigger intervals, possessing the waveform acquisition and time resolution capabilities required for performing dual-pulse relative time delay scanning.

[0053] Simultaneously, a time-dependent solution is performed using a finite element model corresponding to the port under test. The device structure, material parameters, boundary conditions, single-pulse time function, and solution settings are kept consistent across the three operating conditions; only the time offset of the second pulse relative to the first pulse is changed, and the terminal current response within the range of 0–200 ns is extracted. Figure 4Three simulation conditions with relative delays of 0 ns, 80 ns, and 120 ns are given to compare the impact of relative delay on the peak value of the terminal current, the spacing between the two peaks, and the recovery window. Figure 4 As shown in Table 1, the peak current is approximately 1.909 mA when the relative delay is 0 ns; a double-peak response with an interval of approximately 80 ns is observed when the relative delay is 80 ns; and when the relative delay is 120 ns, the second response peak shifts to approximately 142 ns, and the response 10% higher than the peak value persists for approximately 188 ns. Therefore, the effect of the relative delay of the double pulse can be quantified into indicators such as peak value, response width, tailing, integral response, and response time window.

[0054]

[0055] Table 1. Characteristic parameters of terminal current response under different relative time delays

[0056] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any changes made based on the design principles of the present invention, or any non-creative modifications made thereon, shall fall within the scope of protection of the present invention.

Claims

1. A dual-laser time-delay synergistic effect simulation system, characterized in that, include: A dual-pulse delay generation unit is used to generate two pulsed laser beams with a set relative time delay; The beam combining and focusing incident unit is used to combine the two pulsed laser beams in space and focus them onto the same target point of the semiconductor device sample under test. A sampling calibration unit is used to sample the combined optical path to form a calibration signal corresponding to the arrival time of the two pulsed laser beams at the sample surface of the semiconductor device under test and to monitor the laser energy. The sampling calibration unit includes a sampling plate, a beam splitter, an energy meter, a beam demultiplexer, a first photodetector, and a second photodetector. The sampling plate is disposed in the combined optical path and is used to split the sampling beam according to a set ratio. The beam splitter is used to split the sampling beam into two paths, one of which is incident on the energy meter to monitor the pulse energy, and the other is incident on the beam demultiplexer. The beam demultiplexer is used to separate the combined sampling beam into two sub-beams corresponding to the original two pulsed laser beams, and these sub-beams are respectively incident on the first photodetector and the second photodetector to form a calibration signal. The signal processing and measurement unit is used to receive and process the calibration signal to calibrate the set relative time delay, and to acquire and record the transient electrical response data of the semiconductor device sample under test under laser irradiation. The relative delay is adjustable in preset steps within a preset delay window; the signal processing and measurement unit determines the measured delay of the two pulsed laser beams as the effective delay of each scanning point based on the two received calibration signals, and compensates and corrects the set value of the relative delay according to the calibration relationship between the set relative delay and the measured delay; the two pulsed laser beams form a non-simultaneous double-pulse ionization field in the working area of ​​the semiconductor device sample under test to characterize the time synergy effect.

2. The dual-laser time delay synergistic effect simulation system according to claim 1, characterized in that, The dual-pulse delay generation unit includes two independent pulsed lasers and electronic delay units electrically connected to the two pulsed lasers respectively. The electronic delay units are used to provide trigger signals to the pulsed lasers and to set and adjust the relative delay.

3. The dual-laser time delay synergistic effect simulation system according to claim 2, characterized in that, The pulsed laser is configured with a wavelength of 355 nm, 532 nm, or 1064 nm or its equivalent wavelength, with a pulse width of 0.1 to 10 ns, and outputs in a single-trigger mode or a repetitive-trigger mode.

4. The dual-laser time delay synergistic effect simulation system according to claim 1, characterized in that, The beam combining and focusing incident unit includes an orthogonal beam combiner, a main optical path, and an objective lens connected in sequence. The orthogonal beam combiner is used to spatially combine two pulsed laser beams. The main optical path is used to transmit the combined laser beam to the objective lens. The objective lens is used to focus the combined laser beam onto the same target point of the semiconductor device sample under test. Its focal spot diameter is 10-50 μm, and the spatial confocal error is controlled within 1 µm.

5. The dual-laser time delay synergistic effect simulation system according to claim 1, characterized in that, The signal processing and measurement unit includes an oscilloscope, and a first transimpedance amplifier, a second transimpedance amplifier, and a third transimpedance amplifier connected to the oscilloscope. The first transimpedance amplifier is connected to the semiconductor device sample under test and is used to convert the transient current signal generated by the device under laser irradiation into a voltage signal and amplify it. The second and third transimpedance amplifiers are connected to a first photodetector and a second photodetector, respectively, and are used to amplify the calibration signal. The oscilloscope is used to receive the signal from the first transimpedance amplifier to record the transient electrical response data of the device, and simultaneously receive the two calibration signals output by the second and third transimpedance amplifiers. The difference in the arrival time of the leading edges of the two calibration signals is determined as the measured time delay.

6. The dual-laser time delay synergistic effect simulation system according to claim 5, characterized in that, The oscilloscope has a sampling rate of no less than 10 GSa / s and an analog bandwidth of no less than 1 GHz; the bandwidths of the first transimpedance amplifier, the second transimpedance amplifier, and the third transimpedance amplifier are all no less than 1 GHz.

7. A semiconductor characterization method, characterized in that, Using the dual-laser time-delay synergistic effect simulation system according to any one of claims 1 to 6, the following steps are included: S1. Single-beam baseline measurement: Obtain the reference response characteristics of the semiconductor device sample under test when two pulsed lasers act alone; S2. Online time delay calibration and correction: Set the target time delay, collect two calibration signals corresponding to two pulsed lasers, obtain the measured time delay based on the difference in arrival times of the leading edges of the two calibration signals, and establish the calibration relationship between the set time delay and the measured time delay. S3, Dual-beam delay scanning: Scanning is performed within the preset delay window according to the relative delay set in steps. At each scanning point, the measured delay is used as the effective delay, and the transient electrical response data of the device is collected synchronously. S4. Synergistic Effect Determination: At each effective delay point, extract the double-pulse response characteristic quantity of the semiconductor device sample under test under the synergistic effect of the double pulse, and compare it with the reference response characteristic quantity under the same energy conditions; when the deviation of the double-pulse response characteristic quantity relative to the reference response characteristic quantity exceeds the preset determination threshold, it is determined that there is a synergistic effect at the effective delay point, and the time window of the synergistic effect is determined according to the effective delay range that continuously meets the determination conditions; wherein, the synergistic effect includes synergistic enhancement and synergistic suppression, which are determined according to the direction of the response deviation.

8. The semiconductor characterization method according to claim 7, characterized in that, The preset time delay window is determined based on the recovery time of the single-pulse transient response of the semiconductor device under test. During step scanning, a coarse scan is first performed within the preset time delay window using a first time delay step. The candidate synergistic effect time domain interval is determined based on the change of the double-pulse response characteristic quantity with the effective time delay. Then, a fine scan is performed within the candidate synergistic effect time domain interval using a second time delay step smaller than the first time delay step to determine the boundary of the synergistic effect time window and its change characteristics.

9. The semiconductor characterization method according to claim 7, characterized in that, The dual-pulse response characteristics include at least one of the following: event trigger probability, transient current peak value, pulse width, integrated charge, and threshold energy.

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