Quantitative estimation method and system for equivalent LET of pulse laser single event effect

Abstract

The invention belongs to the technical field of pulse laser single event effect testing, and discloses a quantitative estimation method and system for pulse laser single event effect equivalent LET, and the method considers two optical absorption processes of single photon absorption (SPA) and two-photon absorption (TPA). The influence of light beam characteristics, device parameters and material characteristics on light beams in the photon absorption process is analyzed, calculation formulas and parameter definitions are defined, and the LETL under any pulse laser test condition can be accurately estimated. The invention further provides experimental verification steps of the LETL, so that the reliability of a calculation result is ensured. The method provides key technical support for pulse laser testing as a predictive alternative method for heavy ion testing, and has wide application prospects.

Description

Technical Field

[0001] This invention belongs to, but is not limited to, the field of pulsed laser single-event effect testing technology, and particularly relates to a quantitative estimation method and system for the equivalent LET of pulsed laser single-event effect. Background Technology

[0002] Pulsed laser single-event effect (PL SEE) testing has long been used to study the response of circuits to ionizing radiation. It offers advantages such as high spatial selectivity, no need for actual radiation exposure, and easy adjustment of the laser equivalent linear energy transfer (LET). L With its advantages such as [missing information], it has become a commonly used tool for SEE screening, mitigation, and hardening design verification. However, for PL SEE testing to truly become an effective alternative to heavy ion testing, the equivalent LET needs to be accurately and independently determined.

[0003] Existing LET L The computation faces numerous challenges, such as the fact that laser testing employs various testing geometries (e.g., single-photon absorption (SPA) or two-photon absorption (TPA), laser wavelengths, and focusing methods), each with its unique combination of parameters, leading to LET... L The calculation of LET is complex and difficult to standardize. Although some studies have reported on LET... L The calculations are mostly limited to specific test geometries, lacking versatility and accuracy.

[0004] Existing technology discloses a patent CN103884926B, which relates to a method for calculating the equivalent LET value of a pulsed laser, particularly for pulsed laser irradiation from the back of a device. This method defines the equivalent LET of a laser and considers the attenuation law of laser intensity along the incident depth direction. Based on the assumption that each laser photon generates an electron-hole pair under a linear absorption mechanism, and combining reflection and absorption attenuation effects, it finally obtains the E corresponding to the accumulated laser energy in the sensitive region. LET The value is used to evaluate the quantitative effectiveness of laser simulation of single-event effects in engineering applications. This patent explicitly considers physical effects such as substrate attenuation and multiple reflections from front-side metal wiring, and provides methodological support for laser LET estimation under back-side irradiation.

[0005] Despite reasonably considering various physical influencing factors, this method still has core limitations. First, it assumes that each photon generates one electron-hole pair, neglecting the nonlinear absorption mechanism of multiphoton absorption (TPA) under high-intensity laser irradiation. Second, it does not incorporate the spatial dependence of charge collection efficiency (CCE) and device geometry on carrier extraction efficiency, resulting in a lack of rigorous mapping between the estimated LET and experimental charge collection. Furthermore, it lacks a step to compare and verify the laser-estimated equivalent LET with the actual charge collection measured from heavy-ion experiments, thus failing to establish a complete quantitative equivalence mapping in engineering evaluations. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method and system for quantitative estimation of the equivalent LET of single-event effect in pulsed lasers.

[0007] This invention proposes a quantitative estimation method for the equivalent LET of single-event effect in pulsed lasers, which specifically includes:

[0008] S1: Determine the laser testing conditions, including laser parameters, material parameters, and device parameters;

[0009] S2: Select the corresponding LET based on whether the optical absorption process is single-photon absorption (SPA) or two-photon absorption (TPA). L Calculation formula;

[0010] S3: Calculate the equivalent LET of a pulsed laser L .

[0011] Furthermore, the laser parameters include laser wavelength, pulse energy, pulse width, and focused beam size, which are obtained through the following steps:

[0012] (1) Confirm the laser wavelength and the device substrate material;

[0013] (2) Conduct single-event effect experiments with pulsed lasers;

[0014] (3) Record parameters such as single-event effect sensitivity parameters, laser wavelength, and laser energy.

[0015] Furthermore, the material parameters include the SPA coefficient, TPA coefficient, refractive index, energy for generating electron-hole pairs, and material density.

[0016] Furthermore, the device parameters include reflectivity, substrate thickness, and space constraint factor.

[0017] Furthermore, the LET L The general form of the equation is:

[0018]

[0019] Among them, Q max It is the maximum deposited charge (in pC) under given laser conditions; L ax S(z) is the axial length factor (unit: μm), reflecting the axial extent of charge deposition; S(z) is the axial distribution function, describing LET. L The variation with laser propagation distance z; CF is the unit conversion factor, for silicon materials, converting pC / μm to MeV·cm. 2 The coefficient for / mg is 96.5; F SR is the spatial constraint factor, used to correct charge deposition attenuation when the sensitive area of ​​the device is smaller than the lateral allowable portion of the laser carriers; z is the laser propagation distance (unit: μm), calculated from the incident surface of the device.

[0020] For the SPA and TPA absorption processes, the calculations of each factor in the above formula are listed in Table 1 below.

[0021] Table 1 LET L Formulas for calculating each factor

[0022]

[0023] Furthermore, the LET L The validity assessment was performed using LET-based methods. L The estimated collected charge (CC) value from the equation is compared with experimental charge collection data obtained using the test equipment, and the charge collection CC is compared with LET. L The relationship is:

[0024]

[0025] Where CC is the actual charge collected in the pulsed laser single-event effect experiment (unit: pC); z is the laser propagation distance, CCE(z) is the space-dependent charge collection efficiency (dimensionless, 0~1), which is related to the junction electric field and carrier transport characteristics of the device; L is the device substrate thickness (unit: μm), and the integration interval is from the incident surface (z=0) to the bottom of the substrate (z=L). Equation (2) represents LET L The axial integral of the curve and the CCE curve is the coupling result of "energy deposition" and "device charge collection capability". Integration interval (e.g., from 0 to substrate thickness L) and numerical integration method.

[0026] For a given geometry and pulse energy, the calculated LET L The curve is multiplied by an appropriate CCE curve, and then spatial integration is performed over the axial region (i.e., the thickness L from the incident surface to the device substrate) to obtain a single calculated CC value. The specific steps are as follows:

[0027] (1) Using LET L Equation calculation equivalent to LET;

[0028] (2) The charge collection efficiency (CCE) was extracted through experiments. The specific process is as follows:

[0029] (3) Calculate the charge collection amount CC generated during the pulsed laser single-event effect experiment;

[0030] (4) Compare the charge collection amount CC calculated by LET in the heavy ion experiment and analyze the error between CC and CC.

[0031] The testing process for obtaining CCE is as follows:

[0032] ① Selecting experimental conditions:

[0033] Two-photon absorption (TPA) optical geometry is adopted: a 100× microscope objective lens is selected (small focusing spot, high spatial resolution), a 1260nm laser wavelength is used (avoid SPA interference, only excite TPA), and the laser pulse energy is fixed (to ensure stable carrier generation).

[0034] ② Perform Z-scan (axial focusing scan):

[0035] Move the laser focusing position (z) along the laser propagation direction (axis z-axis) in small steps (e.g., 1–5 μm). foc ), covering the entire substrate thickness range of the device (from z=0 to z=L);

[0036] Each move z foc Record the corresponding single-particle transient (SET) signal (acquired using test equipment such as an oscilloscope).

[0037] ③ Data processing: Deconvolution to eliminate the influence of laser carrier distribution

[0038] The carrier distribution generated by TPA is determined by the laser focusing characteristics; by performing deconvolution operation on the SET signal obtained by Z-scan, the influence of the laser carrier distribution is removed, and the charge collection capability curve, namely CCE(z), is obtained only by the spatial characteristics of the device itself.

[0039] Another objective of this invention is to provide a quantitative estimation system for the equivalent LET of single-event effects in pulsed lasers, the system specifically comprising:

[0040] The condition determination module is used to determine laser testing conditions such as laser parameters, material parameters, and device parameters.

[0041] The calculation module is used to calculate the equivalent LET of a pulsed laser. L .

[0042] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0043] This invention provides a universal LET L The estimation method is applicable to various laser testing geometries, including SPA and TPA excitations, overcoming the limitation of existing methods to specific testing conditions. By clarifying the role of each parameter and its calculation formula, LET... L The calculations are more accurate and interpretable, providing a reliable basis for predictive testing. The errors of each parameter and their impact on LET are considered. L The impact of uncertainty helps in assessing the reliability of test results. This method can be widely applied to the evaluation of low-cost, fast-response devices, and can help promote pulsed laser testing as an effective alternative to heavy-ion testing, alleviating the pressure on heavy-ion testing facilities and improving testing efficiency and accessibility. Attached Figure Description

[0044] Figure 1 This is a flowchart of a method for quantitatively estimating the equivalent LET of a single-event effect in pulsed lasers, provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] This invention addresses the inability of existing pulsed laser simulations of single-event effects to achieve laser-deposited energy transfer (LET) to true linear energy transfer (LET). L This paper addresses the equivalent technical bottleneck and proposes an equivalent LET with quantifiable physical basis. L Quantitative estimation method. While traditional pulsed laser simulation techniques can reproduce transient charge perturbations caused by heavy-ion incident radiation on a spatiotemporal resolution scale, the significant difference between the laser energy deposition mechanism in materials and the energy deposition mechanism of charged particles makes it difficult to establish a unified quantitative equivalence standard across different experimental platforms. This method, by introducing optical absorption parameters, material electronic structure parameters, and device reflection and thickness constraints, establishes a quantitative model for the energy transfer from optical energy deposition to material mass, enabling the energy equivalence of laser-induced single-event effects to be estimated in terms of LET. L Dimensional expression provides a physical basis for the correspondence between experimental design and heavy ion irradiation results.

[0047] In terms of working principle, the method first determines whether the optical absorption process is dominated by single-photon absorption or two-photon absorption based on parameters such as the wavelength, pulse energy, and focused beam diameter of the experimental laser, combined with the bandgap characteristics of the device substrate material. When the photon energy corresponding to the wavelength is higher than the bandgap energy, energy deposition mainly follows the single-photon absorption law; while when the photon energy is lower than the bandgap energy, electronic transitions are achieved through a two-photon absorption process. Depending on the absorption type, either a linear absorption coefficient or a two-photon absorption coefficient is selected to establish an analytical model of the spatial distribution of incident light energy in the material, and then the energy deposition density per unit thickness is calculated.

[0048] Based on this, by combining the material density, the average energy of the generated electron-hole pairs, and the reflection loss parameter, the energy deposition distribution can be converted into an equivalent LET. L The effective energy absorbed by the material per unit length is represented by this value, which physically corresponds to the linear energy transfer during heavy ion penetration. The equivalent LET is calculated under different laser parameters. L The curves can be used to obtain the axial distribution characteristics of optical energy deposition, providing input conditions for subsequent charge collection analysis.

[0049] Furthermore, the method introduces a charge collection efficiency curve to represent the equivalent LET. L The curve is multiplied by the charge collection response of the device at different depths, and then integrated over the entire thickness of the sensing body to obtain the charge collection amount. This integration process comprehensively reflects the coupling effect between photoelectric energy deposition and carrier collection dynamics, ensuring that the calculation results reflect not only the energy input but also the actual response characteristics of the device after excitation. The obtained charge collection amount is then compared with the charge collection amount measured by heavy ion experiments to verify the effectiveness and accuracy of the calculation model.

[0050] In terms of system implementation, the quantitative estimation system of this invention consists of a condition determination module and a calculation module. The condition determination module is responsible for extracting and registering laser parameters, material parameters, and device parameters to ensure the correspondence between the optical input and the physical model. The calculation module automatically calls the single-photon or two-photon energy deposition formula according to the input absorption type and performs spatial integration and normalization processing in the built-in energy distribution model. Through modular design, the system can achieve rapid LET under different experimental conditions. L Estimation and parameter sensitivity analysis provide tools to support experimental calibration and model validation.

[0051] This method addresses the long-standing uncertainty in energy equivalence testing of pulsed laser single-event effects (LETs) by establishing a quantifiable mapping between optical energy deposition and heavy-ion energy deposition. Its working mechanism is based on absorption physics and constrained by material band structure and electronic excitation behavior, enabling traceable LET measurements derived from laser parameters. LQuantitative calculations can significantly improve the comparability and physical realism of pulsed laser single-event effect simulations, providing a reliable quantitative basis for the study of radiation hardening and fault mechanisms of space electronic devices.

[0052] In existing single-event effect (LET) research, heavy-ion accelerators are the mainstream method for evaluating the radiation resistance of devices. However, they suffer from significant drawbacks in terms of cost, accessibility, and experimental flexibility. Accelerator resources are limited, and scheduling cycles are long, making it difficult to meet the rapid verification needs of a large number of electronic devices within their development cycles. Furthermore, the LET coverage at different ion energies is limited, making it difficult to achieve high-resolution testing of the full spectrum of LET effects. This problem is particularly prominent in the radiation resistance qualification of aerospace devices, satellite communication chips, and advanced process CMOS devices, directly hindering industrialization and reliability assessment efficiency.

[0053] To address this limitation, simulating single-event effects using pulsed lasers has become an important alternative. However, existing methods lack a unified quantitative standard for equivalence determination, particularly regarding how to convert laser incident energy and material absorption processes into equivalent LET values, which remains uncertain. This makes it difficult to directly map laser simulation test results to heavy-ion test results, weakening their credibility and applicability in engineering applications. Industry urgently needs a quantitative estimation method that can establish an equivalence correlation between laser and heavy-ion tests to achieve comparability and substitutability of test results in practical reliability assessments.

[0054] The quantitative estimation method proposed in this invention introduces an analytical model of the optical absorption mechanism and energy deposition process, taking two typical processes—single-photon absorption and two-photon absorption—as the starting point for calculation, and derives the equivalent LET of pulsed laser. L The mathematical expression of the method is presented. By modeling laser parameters, material parameters, and device parameters from multiple dimensions, the problem of incomparable results under different testing conditions is solved. In particular, under the condition of two-photon absorption dominance, the quantitative analysis of the nonlinear effect of energy deposition establishes a quantitative correspondence between laser energy input and electron-hole pair generation mechanism, thereby significantly improving the applicability of the method to micron- and even nanoscale devices.

[0055] In practical operation, when a laser beam strikes the material surface, some of its energy is reflected, while the remaining energy enters the substrate and is absorbed. For single-photon absorption, the energy deposition process follows a linear decay law, and the absorption depth is related to the material's absorption coefficient. For two-photon absorption, energy deposition exhibits nonlinear enhancement, dependent on the laser pulse energy density and instantaneous power. In either case, the deposited energy is converted into electron-hole pairs, inducing a transient charge effect similar to that of heavy ion incidence. The amount of this charge collected in the device junction region is related to the equivalent LET (Light Thrust). L It is directly related and provides a measurable physical quantity for establishing the mapping between experiments and theories.

[0056] By introducing the charge collection efficiency function (CCE), the device geometry and carrier transport process are incorporated into the model, enabling the calculation results to not only reflect energy deposition but also correspond to observable charge collection signals at the actual circuit level. L The convolution integral of the curve and the CCE curve yields the theoretically calculated charge collection amount, which is then compared with the collection amount obtained in heavy ion experiments, forming a verification loop. This principle ensures the equivalent LET of pulsed laser. L The estimation method is verifiable and reliable in engineering applications.

[0057] This method overcomes the long-standing technical bottleneck of the inability to directly compare laser simulation results with accelerator heavy-ion test results. By establishing a rigorous multi-layered mapping relationship between optical physics, energy deposition, carrier generation, and charge collection, it not only provides a low-cost and high-efficiency alternative for the rapid evaluation of device resistance to single-event effects but also lays the theoretical and methodological foundation for standardized testing procedures and engineering applications. This achievement is expected to have wide applications in aerospace, military, and the manufacturing of high-reliability electronic devices.

[0058] Example 1: As Figure 1 As shown, this embodiment of the invention provides a method for quantitative estimation of the equivalent LET (Light Effort Tolerance) of a pulsed laser single-event effect. The method specifically includes:

[0059] S1: Determine the laser testing conditions, including laser parameters such as laser wavelength, pulse energy, pulse width, and focused beam size, as well as material parameters such as SPA coefficient, TPA coefficient, and refractive index, and device parameters such as reflectivity and substrate thickness.

[0060] S2: Based on the laser testing conditions, determine whether the optical absorption process used is single-photon absorption (SPA) or two-photon absorption (TPA);

[0061] S3: Calculate the equivalent LET of a pulsed laser L .

[0062] LET L It is an axial charge deposition distribution, similar to heavy-ion LET, which is obtained by integrating the carrier distribution generated by the laser along its lateral dimension. The carrier distribution is determined by the optical absorption process (SPA or TPA) and the focusing of the laser beam.

[0063] LET L The general form of the equation is:

[0064]

[0065] For the SPA and TPA absorption processes, the calculations of each factor in the above formula are listed in Table 2 below.

[0066] Table 2 LET L Formulas for calculating each factor

[0067]

[0068] The constants, laser beam parameters, material property parameters, and device property parameters used in the above calculation formulas are listed in Tables 3, 4, 5, and 6 below.

[0069] Table 3. Constants used in calculations

[0070]

[0071] Table 4 Laser Beam Parameters

[0072]

[0073] Table 5 Material property parameters

[0074]

[0075] Table 6 Device Characteristic Parameters

[0076]

[0077] Among them, F SR The core physical significance is to quantify the degree of spatial overlap between the laser-induced lateral distribution of charge carriers and the device's sensitive area, and to correct the charge deposition attenuation caused by "the size of the device's sensitive area being smaller than the lateral diffusion range of charge carriers".

[0078] The charge carriers generated by pulsed laser through SPA / TPA will form a specific distribution in the transverse direction (perpendicular to the laser incident direction). If the transverse dimension of the device's sensitive region is smaller than the transverse distribution range of the charge carriers, some charge carriers will diffuse outside the sensitive region and cannot be collected by the device, resulting in an actual charge deposition amount lower than the theoretical value. SR The value range is 0 <F SR ≤1: When the sensitive region completely covers the transverse distribution of charge carriers, F SR ≈1, no correction needed; when the sensitive region only covers a portion of the carrier distribution, F SR <1, LET needs to be corrected using this factor. L The calculation results are ensured to match the actual charge deposition. Typically, the charge carriers exhibit a Gaussian distribution, and the sensitive region is circular. F SR The calculation formula is:

[0079]

[0080] Where, rs ω is the radius of the circular sensitive area, and ω0 is the size of the focused spot, defined as the light intensity as 1 / e 2 Half the width at that location.

[0081] In order to evaluate LET L The validity of the calculations can be compared using experimental data. For pulsed lasers to effectively replace heavy ion experiments, they need to meet certain requirements within the same pulsed laser LET range. L Comparing the SEE responses generated by lasers and heavy ions under LET (Light Emission Theory) implies that the equivalent LET of the alternative source should be determined independently of heavy ion data. Therefore, an LET-based approach is adopted. L The collected charge (CC) value estimated by the equation was compared with experimental charge collection data obtained using the test equipment.

[0082] Charge collection CC and LET L The relationship is:

[0083]

[0084] Where CCE(z) is the space-dependent charge collection efficiency.

[0085] For a given geometry and pulse energy, the calculated LET L Multiply the curve by an appropriate CCE curve, then perform spatial integration over the axial region to obtain a single calculated CC value. Specific steps:

[0086] (1) Conduct pulsed laser single-event effect experiments and record parameters such as single-event effect sensitivity parameters, laser wavelength, and laser energy;

[0087] (2) Using LET L Equation calculation equivalent to LET;

[0088] (3) The charge collection efficiency (CCE) was extracted through experiments;

[0089] (4) Calculate the charge collection amount CC generated during the pulsed laser single-event effect experiment;

[0090] (5) Compare the charge collection amount CC calculated by LET in the heavy ion experiment and analyze the error between CC and CC.

[0091] Example 2: As Figure 1 As shown, a specific calculation example of the technical solution provided by this invention is as follows:

[0092] 1. Single Photon Absorption (SPA) Calculation

[0093] 1.1 Input Parameters

[0094] Table 7 Laser Parameters

[0095]

[0096] Table 8 Material Parameters (Silicon Substrate)

[0097]

[0098]

[0099] Table 9 Device parameters (taking OSD15-5T photodiode as an example)

[0100]

[0101] Table 10 Physical constants

[0102]

[0103] 1.2 Calculation Steps

[0104] Step 1: Calculate the maximum deposited charge Q max (SPA)

[0105] The laser wavelength is 1064 nm, and the pulse energy J is 649 pJ.

[0106] From the formula:

[0107]

[0108] We can obtain: Q max ≈432fC

[0109] Step 2: Determine the axial length factor L ax Axial distribution function S(z)(SPA)

[0110] Axial length factor: L ax =z PD =1014μm

[0111] Axial distribution function: Take the focal position z = z foc =0, substitute into the formula:

[0112]

[0113] The result is: S(0)≈0.691

[0114] Step 3: Calculate the laser equivalent linear energy transfer (LET) L

[0115] From the formula:

[0116]

[0117] get:

[0118] LET L (0)≈0.0289MeV·cm 2 / mg

[0119] Step 4: Calculate the charge collection amount CC

[0120] Based on the formula:

[0121]

[0122] Assuming uniform charge collection in a large-area device, CCE(z) = 0.8 (typical experimental value), the integral simplification yields:

[0123] CC≈8.67pC

[0124] 1.3 Final Results

[0125] Table 11 SPA Calculation Results

[0126]

[0127] 2. Two-photon absorption (TPA) calculation

[0128] 2.1 Input Parameters

[0129] Table 12 Laser Parameters

[0130]

[0131] Table 13 Material Parameters (Silicon Substrate)

[0132]

[0133]

[0134] Table 14 Device Parameters (Taking FD11A Photodiode as an Example)

[0135]

[0136] 2.2 Calculation Steps

[0137] Step 1: Calculate the maximum deposited charge Q max (TPA formula)

[0138] The absorption coefficient β2 of TPA is 1.2 × 10⁻⁶. -11 cm / W, with pulsed laser energy E = 1500 pJ.

[0139] From the formula:

[0140]

[0141] Therefore, Q max =152fC.

[0142] Step 2: Determine the axial length factor L ax With axial distribution function S(z)(TPA)

[0143] Take the axial length factor L ax =pi×z R ≈672μm, focal position of axial distribution function z=z foc =20μm, substituting into the formula:

[0144]

[0145] Therefore, S(20) = 1.0

[0146] Step 3: Calculate the laser equivalent linear energy transfer (LET) L

[0147] From the formula:

[0148]

[0149] Received, LET L (20)≈0.022MeV·cm 2 / mg

[0150] Step 4: Calculate the charge collection amount CC

[0151] Assuming CCE(z) = 0.75 (typical value for thick substrate devices), according to the formula:

[0152]

[0153] Simplifying by integration, we get CC ≈ 8.25 pC

[0154] 2.3 Final Results

[0155] Table 15 TPA Calculation Results

[0156]

[0157] 3. Physical constants and unit conversion table

[0158] Table 16 Commonly Used Physical Constants

[0159]

[0160] Table 17 Key Unit Conversion Relationships

[0161]

[0162] Example 3: This embodiment of the invention provides a quantitative estimation system for the equivalent LET of single-event effect in pulsed lasers. The system specifically includes:

[0163] The condition determination module is used to determine laser testing conditions such as laser parameters, material parameters, and device parameters.

[0164] The calculation module is used to calculate the equivalent LET of a pulsed laser. L .

[0165] The pulsed laser single-event effect equivalent LET quantitative estimation system described in this embodiment of the invention can be explained from the aspects of laser parameter acquisition, material and device physical process modeling, energy deposition analysis, and charge collection calculation.

[0166] First, the condition determination module establishes complete experimental input conditions by acquiring laser wavelength, pulse energy, pulse width, and focused beam size, combined with material parameters such as device substrate thickness, refractive index, and absorption coefficient. This module ensures that the input variables required for subsequent calculations all come from measurable and controllable physical quantities, thereby guaranteeing the repeatability and traceability of the estimation system.

[0167] The system determines whether the optical absorption process is single-photon or two-photon absorption based on the input parameters provided by the module. When the incident light energy is above the material's band gap, single-photon absorption dominates, and the energy deposition process can be described linearly. When the laser wavelength is long and the single-photon energy is insufficient to cross the band gap, two-photon absorption induces electron-hole pairs, and the energy deposition process becomes nonlinear. The system can automatically switch models according to actual conditions to ensure the correct calculation path.

[0168] In the computation module, the system analytically models the deposition distribution of laser energy within the bulk material of the device. After being attenuated by surface reflection, the incident laser energy enters the material and attenuates exponentially along the depth direction according to the absorption coefficient, or is enhanced quadratically under two-photon interaction. This process is mathematically described by an energy deposition equation, the core of which involves correlating the incident pulse energy with the energy threshold for generating electron-hole pairs, thereby calculating the energy transfer density within the sensitive volume.

[0169] The system incorporates a charge collection efficiency function into the energy deposition model, taking into account junction electric field distribution, carrier recombination, and diffusion effects. The theoretical charge collection rate is obtained by multiplying the equivalent LET curve by the charge collection efficiency function and performing spatial integration. This process maps pure physical energy deposition to electrical output at the device level, ensuring that the estimation results directly correspond to experimentally measured charge collection signals.

[0170] The calculation module compares the theoretically calculated charge collection amount with the charge collection amount obtained from heavy ion experiments. Through error analysis, the accuracy and applicability of the established equivalent LET model can be evaluated. When the error is within an acceptable range, it indicates that the estimation of the laser equivalent LET is consistent with the results of heavy ion experiments, proving that the system can provide an effective alternative when experimental verification is insufficient.

[0171] This system, through the coordinated operation of the condition determination module and the calculation module, forms a complete logical chain from experimental input, physical modeling, energy deposition calculation to electrical output comparison. Its working principle is essentially to establish a quantitative mapping between optical absorption, energy deposition, and charge collection, thereby achieving accurate estimation of the equivalent LET of pulsed lasers. This provides theoretical and engineering support for the rapid verification and reliability assessment of single-event effects in electronic devices.

[0172] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0173] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for equivalent linear energy transfer (LET) of single-event effect in pulsed lasers. L The quantitative estimation method of ) is characterized by, Includes the following steps: Step 1: Determine the laser testing conditions, including laser parameters, material parameters, and device parameters; Step 2: Based on whether the optical absorption process is single-photon absorption or two-photon absorption, select the corresponding equivalent LET. L Calculation formula; Step 3, based on the equivalent LET L The calculation formula yields the equivalent LET of the pulsed laser. L value.

2. The method as described in claim 1, characterized in that, The laser parameters include laser wavelength, pulse energy, pulse width, and focused beam size. The steps for obtaining these parameters include: confirming the laser wavelength and the device substrate material, conducting pulsed laser single-event effect experiments, and recording single-event effect sensitive parameters and laser energy parameters.

3. The method as described in claim 1, characterized in that, The material parameters include single-photon absorption coefficient, two-photon absorption coefficient, refractive index, energy for generating electron-hole pairs, and material density.

4. The method as described in claim 1, characterized in that, The device parameters include reflectivity, substrate thickness, and space confinement factor.

5. A calculation method for equivalent linear energy transfer due to single-event effect in pulsed lasers, characterized in that, The equivalent LET L The general form of the equation is: Equivalent LET L It equals the energy deposition of the incident photon in the material divided by the mass of the material per unit thickness; where, in the case of single-photon absorption, the energy deposition of the incident light is calculated using the single-photon absorption coefficient, and in the case of two-photon absorption, the energy deposition of the incident light is calculated using the two-photon absorption coefficient.

6. The method as described in claim 5, characterized in that, The equivalent LET obtained through calculation L The charge collection efficiency curve is multiplied by the charge collection efficiency curve and integrated over the axial region to obtain the charge collection amount. This charge collection amount is compared with the experimentally obtained heavy ion charge collection amount to evaluate the equivalent LET. L The validity of the calculation results.

7. A method for applying single-event effect equivalent LET to pulsed lasers L A quantitative estimation system, characterized in that, include: The condition determination module is used to determine laser parameters, material parameters, and device parameters; The calculation module is used to calculate the equivalent LET of a pulsed laser based on the optical absorption type and corresponding formula. L .

8. The system as described in claim 7, characterized in that, The condition determination module is used to obtain the laser wavelength, pulse energy, pulse width, and focused beam size, and to match them with the device substrate material.

9. The system as described in claim 7, characterized in that, The calculation module further includes a charge collection calculation unit for calculating the amount of charge collected based on the equivalent LET. L The amount of charge collected is calculated by integrating the curve with the charge collection efficiency curve.

10. An equivalent LET based on any one of claims 1 to 9 L The application of quantitative estimation methods or systems in reliability testing of single-event effects in pulsed lasers is characterized by, The calculated charge collection rate is compared with the experimental heavy ion charge collection rate to verify and evaluate the device's resistance to single-event effects.

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