An accelerated method for composite environmental testing involving long-term low-dose rate irradiation

Abstract

The present invention relates to a composite environment test acceleration method containing long-term low-dose rate irradiation. The method uses temperature step irradiation to identify the low-dose rate damage enhancement (ELDRS) effect of bipolar process devices, and uses hydrogen injection as an acceleration condition for composite environment ground simulation tests. Based on the characterization of radiation damage factors, accelerated simulation tests are performed on devices with low-dose rate damage enhancement (ELDRS) tendencies to solve the problem of over-underestimation of device radiation resistance in high-dose rate simulation tests. High-dose rate / injection rate irradiation tests are performed on devices immune to low-dose rate damage enhancement (ELDRS‑fre) to avoid the problem of over-overestimation of device radiation resistance caused by accelerated simulation tests. Based on the matching relationship between hydrogen injection concentration and irradiation dose rate, test conditions for accelerated evaluation are extracted to achieve accelerated evaluation of bipolar devices in composite environments, taking into account displacement damage effect and ELDRS effect. The method of the present invention can shorten the test cycle, save costs, and improve the reliability of device radiation resistance evaluation.

Description

Technical Field

[0001] The present invention relates to a composite environment test acceleration method including long-term low-dose rate irradiation, belonging to the fields of microelectronic technology and radiation resistance technology. Background Art

[0002] Electronic devices used in space must undergo rigorous radiation resistance performance evaluation to ensure that they meet the radiation resistance requirements of space missions. The evaluation of space radiation damage is achieved through ground simulation tests to achieve the same or similar characterization as in space. The actual space is a multi-particle, low-dose rate composite environment, which has a long-term combined effect of multiple radiation effects on electronic devices. The combined effects of different effects need to be considered in ground simulation tests. The simulation test evaluation of electronic devices in a composite environment is one of the key issues to ensure the reliable operation of satellite electronic devices.

[0003] Studies have shown that space rays and particles can produce various radiation effects on bipolar analog circuits, such as total ionizing dose radiation effect, displacement damage radiation effect, and single particle effect. Among them, the total ionizing dose effect and displacement damage effect are the main problems faced by bipolar devices in space applications. In addition, the low dose rate damage enhancement effect (Enhanced low Dose Rate Sensitivity, ELDRS) of bipolar devices has exacerbated the total dose effect problem of bipolar devices used in aerospace. The low dose rate damage enhancement effect (ELDRS) is different from the time-related effect of MOS devices. The difference in effects between different dose rates cannot be eliminated by room temperature annealing after high-dose irradiation. If the dose rate factor is not considered, the evaluation of the total ionizing dose effect of bipolar devices may be underestimated. The typical dose rate distribution range of the Earth orbit is 10 -4 -10 -2 rad(Si) / s, the dose rate in deep space environment is even lower. In order to characterize the special low-dose rate damage enhancement effect of bipolar devices, relevant experts at home and abroad have developed accelerated evaluation methods such as variable dose rate accelerated evaluation test methods, high temperature irradiation test methods, variable temperature accelerated evaluation methods and H2 atmosphere irradiation. These methods can achieve the same effect as low-dose rate irradiation in a shorter time. However, the above methods are only applicable to the independent evaluation of low-dose rate damage enhancement effect, and the accelerated evaluation of low-dose rate damage enhancement effect (ELDRS) effect is not included in the comprehensive simulation test of total ionization dose effect and displacement effect.

[0004] The increase of interface traps as recombination centers caused by ionizing radiation under low dose rate conditions is the direct cause of the low dose rate damage enhancement (ELDRS) effect, and the microscopic response characteristics of the interface trap charge are the key to the generation of the EDLRS effect. Through research, it is found that temperature and hydrogen concentration are closely related to radiation-induced defect charges. By regulating the hydrogen concentration and temperature, the ELDRS effect of the device can be accelerated to evaluate the ELDRS effect, reduce the dependence of radiation damage on dose rate, and shorten the test cycle. In addition, the dose rate / injection rate of the incident particles does not affect the displacement effect of the bipolar device. Therefore, the present invention identifies whether the bipolar device has a low dose rate damage enhancement (ELDRS) effect by comparing the test methods of temperature and hydrogen injection, extracts the dose rate and hydrogen concentration required for the ground simulation test based on the damage degree of the two, and realizes the accelerated evaluation of bipolar devices under a composite environment, taking into account the displacement damage effect and the low dose rate damage enhancement effect in the total ionization dose effect. Summary of the invention

[0005] The purpose of the present invention is to provide an accelerated test evaluation method for bipolar devices under a composite environment based on the key generation mechanism of the total ionization dose effect and the displacement damage effect. The method is based on the physical mechanism of radiation-induced charge generation involving temperature and hydrogen ions, accelerates the evolution process of interface trap charges formed at the Si / SiO2 interface, increases the dose rate conditions of the ground comprehensive irradiation test, shortens the evaluation time of the total ionization dose effect, and does not affect the evaluation results of the displacement damage effect of the bipolar device. The method first uses temperature step irradiation to identify the low dose rate damage enhancement (ELDRS) effect of the device, and conducts accelerated simulation tests on devices with low dose rate damage enhancement (ELDRS) tendencies to solve the problem of underestimating the device's radiation resistance in high dose rate simulation tests. High dose rate / injection rate irradiation tests are performed on low dose rate damage enhancement immune (ELDRS-free) devices to solve the problem of overestimating the device's radiation resistance caused by accelerated simulation tests. Then, based on the parameter degradation comparison results of temperature step irradiation and hydrogen injection irradiation, the dose rate and hydrogen concentration required for the ground simulation test in a composite environment are extracted to ensure accurate evaluation of bipolar devices in a low dose rate composite environment.

[0006] The invention discloses a composite environment test acceleration method including long-term low-dose rate irradiation, which is carried out according to the following steps:

[0007] Sample initial testing and depackaging:

[0008] a. First, the bipolar sample is subjected to an electrical parameter test, then the bipolar sample is removed from the package, and then the electrical parameter test is performed on the sample again. The electrical parameters of the bipolar sample are kept consistent before and after the sample is removed from the package;

[0009] Independent total ionizing dose irradiation test:

[0010] b. The samples processed in step a are subjected to independent 60 Co-γ ray ionizing total dose irradiation test, including temperature step irradiation test, hydrogen injection irradiation test, and room temperature high dose rate irradiation test, wherein the temperature step irradiation test adopts a dose rate range of 2-5rad(Si) / s and a temperature range of 120-80°C, the hydrogen injection irradiation test adopts a dose rate range of 10-50rad(Si) / s, and the room temperature high dose rate irradiation test adopts a dose rate range of 50-300rad(Si) / s;

[0011] c. After the irradiation, electrical parameter testing, data processing, damage enhancement factor calculation and low-dose rate damage enhancement effect identification are carried out;

[0012] Accelerated irradiation conditions extraction:

[0013] d. Based on the radiation damage under the temperature step irradiation test and hydrogen injection irradiation test conditions in step b, the test conditions for accelerated evaluation of samples under a composite environment are obtained through the matching relationship between hydrogen injection concentration and irradiation dose rate, including hydrogen injection concentration and dose rate / injection rate;

[0014] Ground simulation test of composite environment or single charged particle:

[0015] e. If the sample is identified as a low-dose rate damage enhancement effect sample in step c, select samples from the same batch and repeat step a according to the irradiation test conditions obtained in step d. 60 Ground simulation test of Co-γ-neutron composite environment or single charged particles, where the charged particles are electrons and protons;

[0016] f. If the sample identified in step c is a low-dose rate damage-enhanced immune sample, select the same batch of samples and repeat step a. 60 Ground simulation test of Co-γ-neutron composite environment or single charged particles, where the charged particles are electrons and protons.

[0017] The error of the change of electrical parameters before and after the sample treatment in step a should be within ±10%.

[0018] The present invention discloses a composite environment test acceleration method including long-term low-dose rate irradiation, wherein step c of the method is specifically as follows:

[0019] High dose rate irradiation test data processing: Calculate the average value ΔP of the electrical parameter change at each dose point Ti of each group of test samples Ti , and use it as the vertical axis and the radiation dose as the horizontal axis to draw a high dose rate irradiation test curve, such as Figure 2 HDR curve shown;

[0020] Temperature step irradiation test data processing: Calculate the average value ΔQ of the electrical parameter change at each dose point Ti of each group of test samples Ti , and use it as the vertical axis and the irradiation dose as the horizontal axis to draw a temperature step irradiation test curve, such as Figure 2 TSI curve shown;

[0021] Hydrogen injection irradiation test data processing: Calculate the average value ΔH of the electrical parameter change at each dose point Ti of each group of test samples Ti , and use it as the vertical axis and the irradiation dose as the horizontal axis to draw the hydrogen injection irradiation test curve, such as Figure 2 HSI curve shown;

[0022] Calculation of damage enhancement factor and identification of ELDRS effect: Calculation of damage enhancement factor EF for each parameter of temperature step irradiation test and high dose rate irradiation test, EF = ΔQ Ti / ΔP Ti If EF>1.5, the device is identified as a low-dose-rate damage enhancement (ELDRS) device; if EF<1.5, the device is identified as a low-dose-rate damage enhancement (ELDRS) immune device, that is, a low-dose-rate damage enhancement (ELDRS-free) device.

[0023] The present invention discloses a composite environment test acceleration method including long-term low-dose rate irradiation. In this method, in the face of a complex environment with multiple particles and low dose rates in space, the combined effects of different radiation effects (such as total ionization dose effect, displacement damage effect, etc.) need to be considered in ground simulation tests. In addition, bipolar process devices have a special low-dose rate damage enhancement effect, which aggravates the total ionization dose effect of the device. The present invention establishes a composite environment test acceleration method including long-term low-dose rate irradiation, which can take into account both the displacement damage effect and the low-dose rate damage enhancement effect, and can provide technical support for the accurate evaluation of bipolar process devices in a space radiation environment.

[0024] The invention discloses a composite environment test acceleration method including long-term low-dose rate irradiation, and the beneficial effects of the method are as follows:

[0025] 1. Charged particles in space interact with bipolar process devices, resulting in both ionization energy loss and non-ionization energy loss. A single particle simultaneously produces ionization and displacement effects, and the two interact with each other. In addition, space is a low-dose rate environment. Due to their special low-dose rate damage enhancement effect, ground simulation test evaluations tend to underestimate the radiation resistance of bipolar process devices. The present invention is based on the physical mechanism of radiation-induced defects, accelerates the growth of trap charges on key defect interfaces, takes into account displacement damage effects, and establishes an accelerated evaluation method for composite environmental tests involving long-term low-dose rate irradiation.

[0026] 2. Regarding the total ionization dose effect, considering that hydrogen injection will cause an increase in the interface trap charge that serves as the recombination center, resulting in an overly conservative evaluation result for devices immune to EDLRS, the present invention conducts an independent simulation test on the total ionization dose effect based on the physical mechanism of the generation, transport and mutual transformation of movable particles in the oxide layer, and determines the irradiation conditions of the device during the charged particle simulation test based on the damage enhancement factor, thereby avoiding the problem of overly conservative evaluation of the total dose effect and more accurately evaluating the radiation resistance of bipolar process devices in the actual space environment.

[0027] See attached picture

[0028] Figure 1 is a flow chart of the test method of the present invention;

[0029] Figure 2 It is a schematic diagram of the experimental data processing of the present invention;

[0030] Figure 3 The electrical parameter test of the sample before and after the treatment of the present invention;

[0031] Figure 4 The calculation of the damage enhancement factor of the present invention;

[0032] Figure 5 This is the evaluation result of the accelerated test in the composite environment containing low dose rate of the present invention. DETAILED DESCRIPTION

[0033] The accelerated evaluation method for a composite environmental test including long-term low-dose rate irradiation provided by the present invention is further described below in conjunction with the accompanying drawings.

[0034] Example

[0035] Sample initial testing and depackaging:

[0036] a. First, test the electrical parameters of the bipolar sample, then remove the package of the bipolar sample, and then test the electrical parameters of the sample. The electrical parameters of the bipolar sample before and after the sample is removed from the package remain consistent, and the error of the electrical parameter change should be within ±10%; the device parameters are based on the test method of bipolar transistors in Part 7 of the "Semiconductor Discrete Devices and Integrated Circuits" standard, and the test items are selected as follows: Gummel curve I B &I C -V BE ,like Figure 3 As shown in the figure, the electrical parameters of the sample before and after treatment do not change by more than ±10%. The V BE =Current gain at 0.7V;

[0037] Independent total ionizing dose irradiation test:

[0038] b. The samples processed in step a are subjected to independent 60 Co-γ ray ionizing total dose irradiation test, including temperature step irradiation test, hydrogen injection irradiation test, and room temperature high dose rate irradiation test, wherein the temperature step irradiation test adopts a dose rate range of 2-5rad(Si) / s and a temperature range of 120-80°C, the hydrogen injection irradiation test adopts a dose rate range of 10-50rad(Si) / s, and the room temperature high dose rate irradiation test adopts a dose rate range of 50-300rad(Si) / s;

[0039] c. After the irradiation, electrical parameter testing, data processing, damage enhancement factor calculation and low-dose rate damage enhancement effect identification are carried out;

[0040] Test data processing method: process the changes of electrical parameters under different irradiation conditions respectively. For high-dose irradiation tests, calculate the average value ΔP of the changes of electrical parameters at each dose point Ti of each group of test samples. Ti ; For the temperature step irradiation test, calculate the average value ΔQ of the electrical parameter change at each dose point Ti of each group of test samples Ti ; For the hydrogen implantation irradiation test, calculate the average value ΔH of the electrical parameter change at each dose point Ti of each group of test samples Ti ;

[0041] Calculation method of damage enhancement factor and identification of low dose rate damage enhancement (ELDRS) effect: Calculate the damage enhancement factor EF of each parameter in temperature step irradiation test and high dose rate irradiation test, EF=ΔQ Ti / ΔP Ti The calculation results show that the damage factor EF>1.5, and the device has a low-dose rate damage enhancement (ELDRS) effect. The low-dose damage enhancement effect needs to be considered in the ground simulation test, and accelerated tests should be carried out, such as Figure 4 As shown;

[0042] Accelerated irradiation conditions extraction:

[0043] d. Based on the radiation damage under the temperature step irradiation test and hydrogen injection irradiation test conditions in step b, the test conditions for accelerated evaluation of samples under a composite environment are obtained through the matching relationship between hydrogen injection concentration and irradiation dose rate, including hydrogen injection concentration and dose rate / injection rate;

[0044] Ground simulation test of composite environment or single charged particle:

[0045] e. The sample identified in step c is a low dose rate damage enhancement (ELDRS) effect sample, and samples from the same batch are selected and step a is repeated according to the irradiation test conditions obtained in step d. 60 Ground simulation test of Co-γ-neutron composite environment;

[0046] Figure 5 The present invention extracts the irradiation conditions through step d, 60 The test results after Co-γ-neutron composite environment irradiation. This test takes into account the displacement damage effect of bipolar process devices and their special low-dose rate damage enhancement effect and displacement damage effect, which can shorten the test cycle, save costs and improve the reliability of device radiation resistance performance evaluation;

[0047] f. If the sample identified in step c is a low-dose rate damage-enhanced immune sample, select the same batch of samples and repeat step a. 60 Ground simulation test of Co-γ-neutron composite environment or single charged particles, where the charged particles are electrons and protons.

Claims

1. A composite environmental test acceleration method including long-term low-dose rate irradiation, characterized in that: Follow these steps: a. Sample initial test and de-packaging: First, the bipolar sample is tested for electrical parameters, then the bipolar sample is de-packaged, and then the sample is tested for electrical parameters. The electrical parameters of the bipolar sample are kept consistent before and after the sample is de-packaged; b. Independent total ionizing dose irradiation test: The samples treated in step a are subjected to independent 60 Co-γ ray ionizing total dose irradiation test, including temperature step irradiation test, hydrogen injection irradiation test, and room temperature high dose rate irradiation test, wherein the temperature step irradiation test adopts a dose rate range of 2-5rad(Si) / s and a temperature range of 120-80°C, the hydrogen injection irradiation test adopts a dose rate range of 10-50rad(Si) / s, and the room temperature high dose rate irradiation test adopts a dose rate range of 50-300rad(Si) / s; c. After the irradiation, electrical parameter testing, data processing, damage enhancement factor calculation and low-dose rate damage enhancement effect identification are carried out; d. Extraction of accelerated irradiation conditions: Based on the radiation damage under the temperature step irradiation test and hydrogen injection irradiation test conditions in step b, the test conditions for accelerated evaluation of devices under a composite environment are obtained through the matching relationship between hydrogen injection concentration and irradiation dose rate, including hydrogen injection concentration and dose rate / injection rate; e. Ground simulation test of composite environment or single charged particle: If the sample is identified as a low dose rate damage enhancement effect sample in step c, select the same batch of samples, repeat step a, and conduct the irradiation test according to the irradiation test conditions obtained in step d. 60 Ground simulation test of Co-γ-neutron composite environment or single charged particles, where the charged particles are electrons and protons; f. If the sample identified in step c is a low-dose rate damage-enhanced immune sample, select the same batch of samples and repeat step a. 60 Ground simulation test of Co-γ-neutron composite environment or single charged particles, where the charged particles are electrons and protons.

2. The method for accelerating a composite environment test involving long-term low-dose rate irradiation according to claim 1, characterized in that The error of the change of electrical parameters before and after the sample treatment described in step a should be within ±10%.

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