一种国产GaAs/Ge太阳电池的总剂量辐照特性

对一种国产金属有机物化学气相沉积(MOCVD)工艺制备的GaAs／Ge太阳电池进行了1Mev电子辐照损伤研究，讨论和分析了电池电参数和光谱响应的衰降规律和原因并与常规硅太阳电池作了比较。实验结果表明，GaAs/Ge电池与常规Si电池相比，不但转换效率高而且其抗辐射能力也比Si电池好。另外，带有AlxGa1-xAs窗口层的GaAs电池的辐射损伤机理与Si电池不同。     

典型DC/DC电源变换器电离辐射效应研究

研究了典型DC/DC电源变换器辐照后不同输出负载、不同输入电压等测试条件下,DC/DC电源变换器输出电压等参数变化情况与辐照剂量之间的关系.研究结果表明,DC/DC电源变换器输出电压衰减程度随输出负载功率增大;输入电压变化对输出电压特性的影响程度较小.     

高压偏移栅PMOSFET击穿电压的电离辐照响应

揭示了辐照引起击穿电压变化的机制,提出了提高高压偏移栅PMOSFET击穿电压抗电离辐照的方法。对辐照后击穿电压退火特性进行了研究。     

A study on the degradation of GaAs/Ge solar cells irradiated by <200 keV protons

Damage effects in GaAs/Ge solar cells irradiated by <200 keV protons were studied by measuring their electrical properties and spectral response together with SRIM simulations. Proton energies of 40, 70 and 170 keV were chosen. Experimental results show that the short circuit current, open circuit voltage and maximum power decrease with increasing proton fluence. The degradation of the open circuit voltage is highest for 70 keV irradiation and lowest for 40 keV irradiation. The degradation of short circuit current decreases with increasing proton energy. According to SRIM simulations and spectral response analysis, the above changes in electrical properties are mainly related to damage in different regions of the solar cells.     

Ge nanocrystals embedded in SiO2 in MOS based radiation sensors

In this work, the effects of gamma radiation on the Raman spectra of Ge nanocrystals embedded in SiO₂ have been investigated. SiO₂ films containing nanoparticles of Ge were grown using the r.f.-magnetron sputtering technique. Formation of Ge nanocrystals was observed after high temperature annealing in an inert atmosphere and confirmed by Raman measurements. The intensity of the Raman signal originating from Ge nanocrystals was found to decrease with increasing gamma radiation. The study also includes the gamma radiation effects on MOS structure with Ge nanocrystals embedded in SiO₂. The gamma radiation effects from 500 up to 4000 Gray were investigated. Capacitance-voltage measurements were performed and analyzed. Oxide traps and interface trap charges were calculated. Results show that MOS structure with Ge nanocrystals embedded in SiO₂ is a good candidate to be used in radiation sensors, especially at high radiation doses.     

A study on the effects of the proton flux on the irradiated degradation of GaAs/Ge solar cells

Low-energy proton irradiation is one of the important factors which affect applications of GaAs solar cells in space. The proton flux encountered in orbit is much lower than that used during ground-base radiation experiments, thus ground-based experiments are a so-called accelerated simulating process. In this paper, effects of the proton flux on the degradation of GaAs/Ge solar cells using I-V measurements are investigated. The results indicate that low-energy irradiation seriously damages the solar cells. Regardless of the proton energy, the radiation flux shows no influence on the degradation process of the solar cell. The mechanisms for these effects are discussed in detail here.     

离子辐照GaAs的光致发光和拉曼散射研究

利用250 keV质子和4.5 MeV氪离子(Kr17+)辐照未掺杂GaAs,注量分别为1×10~(12)-3×10~(14) cm~(-2)和3×10~(11)-3×10~(14) cm~(-2),使用光致发光谱和拉曼散射谱分析表征。发光谱的结果表明,随着剂量增大,质子辐照后的CAs峰及其声子伴线逐渐减弱,913 nm处的复合缺陷峰则先增大后减小,此峰与材料制备时的Cu掺杂无关。Kr离子辐照后本征发光峰则完全消失。拉曼散射谱的结果表明,相比于质子辐照,Kr离子辐照后LO声子峰峰位向低频方向移动,出现非对称性展宽,晶体结构发生明显改变。质子和Kr离子辐照效应的差异是由于移位损伤相差至少三个量级造成的。最后采用多级损伤累积(Multi-step damage accumulation,MSDA)模型得到了材料内缺陷的演化过程,并很好地解释了随损伤剂量增大GaAs光学性能及晶体结构的变化趋势。     

电子辐照GaInP/GaAs/Ge三结太阳电池少子寿命的变化

为研究电子辐照空间太阳电池的损伤机制,对电子辐照GaInP/GaAs/Ge三结太阳电池进行了光致发光谱测量,分析了GaInP顶电池及GaAs中间电池发光强度随电子注量的变化规律。利用辐射效率关系对归一化发光强度随电子辐照注量的变化进行了拟合,分别得到了GaInP顶电池及GaAs中间电池在不同辐照条件下的少子非辐射复合寿命τ_nr,通过对比辐照前后少子非辐射复合寿命的衰降变化,发现GaInP顶电池的抗辐照性能优于GaAs中间电池。     

砷化镓体效应二极管中子辐照效应

本文研究了C、X和KQ等波段体效应二极管的中子辐照损伤效应。实验观察到中子辐照环境中体效应二极管低场电阻变大,工作电流和射频输出下降,VI特性变化,甚至使负阻特性消失。实验认为,器件性能退化是由中子辐照砷化镓材料的载流子去除效应引起的。     

Effect of γ-radiation on HfO2 based MOS capacitor

Radiation effects on Metal Oxide Semiconductor (MOS) capacitors with a HfO₂ gate insulator have been studied. Because HfO₂ is a promising high-k dielectric material for microelectronic applications, radiation effects on its performance in MOS devices is of interest. New results on radiation effects on HfO₂, particularly at low gamma radiation doses, are presented. The results are compared with other systems including those of Al₂O₃ plus silicon based Si MOS capacitors. Both devices with different gate thicknesses were irradiated with Co-60 gamma source for varying exposure time. The midgap and flatband voltage shifts in these devices were measured and analyzed. Results show that gamma radiation does not cause significant variations in the HfO₂ MOS especially at low doses.     

On the design of a monolithic 4-bounce high resolution X-ray monochromator

A monolithic monochromator (+n, −n, −m, +m) made of a single block of Ge crystal designed for CoK_α1 radiation was developed and tested numerically and experimentally by means of X-ray diffraction. The advantage of monolithic devices is their mechanical stability and the alignment of such optics is much easier than with polylithic optics, but the development of these devices is rather demanding. The presented monochromator belongs to a group of coplanar in-line devices, which means that the input beam is parallel with the output beam. For the estimation of the spectral and angular properties of a diffracted beam of this monochromator (such as bandpass width, output divergence and input acceptance) we used a numerical approach which we call spectral-angular function. It takes into account both the vertical and the horizontal divergence of the input radiation and uses two-beam X-ray dynamical theory of diffraction. Experimentally, the monochromator was tested by means of X-ray diffraction (synchrotron radiation testing) and the results from this characterization are presented. The influence of the vertical divergence on the spectral distribution of the diffracted beam is discussed and compared with previously published analytical results.     

A comparative study of gamma radiation effects on ultra-low input bias current linear circuits under biased conditions

Ultra-low input bias current linear circuits are used in several applications requiring them to work under varying conditions of temperature, humidity, radiation etc. which influence their performance. This paper presents a first time study of gamma radiation effects on ultra low input bias current linear circuits under biased conditions for small signal dc applications. Under biased conditions, radiation-induced photo currents play a significant role. A noncatastrophic radiation leakage environment has been considered. The linear circuits selected are of different makes and have different input stages, such as those based on JFET and MOS structures. Variations of dc characteristic parameters, such as input offset voltage and input bias current have been studied. Extensive experimental results are presented, including the effects of annealing, on critical parameters. It is seen that these devices behave differently on exposure to gamma radiation, depending on the structure of their input stage. The MOSFET-based stages show a greater change in input offset voltage, whereas FET-based input stages exhibit a greater change in input bias currents. Chopper stabilised linear circuits exhibit lesser deviation in their offset voltages and bias currents due to an inherent chopping action at their input stage that automatically compensates for any variations in these parameters.     

Predicted Effects of Neutron Irradiation on GaAs Junction Field Effect Transistors

The fast-neutron-induced degradation of the properties of n-channel GaAs junction field effect transistors (JFET) is estimated and the results are compared with the effects produced in n-and p-channel silicon field effect transistors. The estimated degradation of the maximum transconductance, maximum drain current, pinch-off voltage, and cutoff frequency is based on electrical measurement data taken for fast-neutron-irradiated bulk n-type GaAs samples. It is concluded that n-channel GaAs JFET's should be at least as resistant to fast neutrons as either n-or p-channel Si JFET's.     

不同设计参数MOS器件的射线总剂量效应

采用非加固工艺，通过设计加固手段实现具有辐射容忍性能的器件，可使器件抗辐射加固成本大为降低。本工作研究商用标准0.6μm体硅CMOS工艺下不同设计参数的MOS晶体管的γ射线总剂量辐照特性。通过对MOS器件在不同偏置情况下的总剂量辐照实验，分别对比了不同宽长比（W/L）NMOS管和PMOS管的总剂量辐照特性。研究表明，总剂量辐照引起阈值电压的漂移量对NMOS及PMOS管的W/L均不敏感；总剂量辐照引起亚阈区漏电流的增加随NMOS管W/L的减小而增加。研究结果可为抗辐射CMOS集成电路设计中晶体管参数的选择提供参考。     

A study on the electric properties of single-junction GaAs solar cells under the combined radiation of low-energy protons and electrons

Displacement damage induced by charged particle radiation is the main cause of degradation of orbital-service solar cells, while the radiation-induced ionization shows no permanent damage effect on their electrical properties. It is reported that in single crystal silicon solar cells, low-energy electron radiation does not exert permanent degradation of their properties, but the fluence of electron radiation exerts an influence on the damage magnitude under the combined radiation of protons and electrons. The electrical properties of the single-junction GaAs/Ge solar cells were investigated after irradiation by sequential and synchronous electron and proton beams. Low-energy electron radiation showed no effects on the change of the solar cell properties during sequential or synchronous irradiation, implying ionization during particle radiation could not exert influence on the displacement damage process to the solar cells under the experimental conditions.     

钝化层结构对氚辐伏电池转换性能的影响

在辐射伏特效应同位素电池(辐伏电池)中,器件的辐伏转化性能不仅受限于换能器件所用的半导体材料、结构或加载放射源的种类,还受换能器件表面钝化层结构的影响。为在氚化钛源加载的平面单晶硅PN结辐伏电池(氚辐伏电池)中得到最佳的钝化效果,本文设计了3种不同的钝化层结构,考察其初始输出性能和抗辐射性能,并单独研究了氚化钛源出射的X射线对单晶硅换能器件的辐射损伤。结果显示:在辐伏电池初始输出性能方面,Si/SiO2/Si3N4结构Si/B-Si glass/Si3N4结构Si/Si3N4结构;在抗氚化钛源辐射损伤方面,Si/Si3N4结构Si/B-Si glass/Si3N4结构Si/SiO2/Si3N4结构,Si/B-Si glass/Si3N4结构具有最佳的抗X射线辐射衰减性能。氚化钛源出射的X射线对辐射损伤效应起主要作用,XPS结果显示,X射线长时间辐照造成了单晶硅表面平整性的破坏。     

Effects of 0.28-2.80 MeV proton irradiation on GaInP/GaAs/Ge triple-junction solar cells for space use

GaInP/GaAs/Ge triple-junction solar cells were irradiated with 0.28, 0.62 and 2.80 MeV protons with fluences ranging from 1 × 10¹⁰ cm⁻² to 1 × 10¹³ cm⁻². Their performance degradation is analyzed using current-voltage characteristics and spectral response measurements. The degradation rates of the short circuit current, open circuit voltage, and maximum power output increase with fluence, but decrease with increasing proton energy. It was also observed that the spectral response of the GaAs middle cell degrades more significantly than that of the GaInP top cell.     

双极电压比较器低剂量率辐照损伤增强效应的变温辐照加速评估方法

对3款同种型号不同公司生产的双极电压比较器进行了高、低剂量率及变温辐照的⁶⁰Co γ辐照实验。结果表明：偏置电流和电源电流为双极电压比较器辐射敏感参数,失调电压仅在工作偏置条件下为辐射敏感参数;由于工艺不同,不同公司的双极电压比较器存在辐射响应差异,而同一公司的双极电压比较器在不同偏置条件下的辐照损伤趋势亦不同;变温辐照加速评估方法不仅可鉴别上述不同公司的双极电压比较器在不同偏置条件下的剂量率效应,而且能很好地模拟和保守地评估其低剂量率下的辐照损伤。     

辐照温度对双极线性稳压器的辐射效应影响

为研究辐照温度对线性稳压器的电离辐射效应的影响,选取三个公司生产的同一型号线性稳压器7805在不同温度条件下进行60Co?电离辐射效应试验。结果表明:辐照温度的增加使三款线性稳压器输出电压的辐射损伤增大;使国家半导体公司和安森美半导体公司稳压器的线性调整率及国家半导体公司的输入电流敏感参数的辐射损伤减小。结合双极晶体管的空间辐照效应模型,对双极线性稳压器不同温度条件下的辐射损伤效应进行了分析和讨论,表明辐照温度对线性稳压器的辐射敏感参数的影响主要取决于陷阱电荷。     

Thin Film Silicon on Silicon Nitride for Radiation Hardened Dielectrically Isolated Misfet's

The permanent ionizing radiation effects resulting from charge trapping in a silicon nitride isolation dielectric has been determined for a total ionizing dose up to 107 rads (Si). Junction FET's, whose active channel region is directly adjacent to the siliconsilicon nitride interface, were used to measure the effects of the radiation induced charge trapping in the Si3N4 isolation dielectric. The JFET saturation current and channel conductance versus junction gate voltage and substrate voltage were characterized as a function of the total ionizing radiation dose. The experimental results on the Si3N4 are compared to results on similar devices with SiO2 dielectric isolation. The ramifications of using the silicon nitride for fabricating radiation hardened dielectrically isolated MIS devices are discussed.