双极型运算放大器ELDRS效应试验研究

针对空间辐射环境下应用的双极型器件抗辐射能力与地面高剂量率辐照模拟试验所获得器件的抗辐照水平存在差异,在地面利用^(60)Co辐射源开展了双极型运算放大器的总剂量辐照试验研究,分析了辐照剂量率、辐照偏置和室温退火3种试验组合条件下样品的总剂量响应。结果表明,在300Gy的辐照水平下,低剂量率辐照条件下器件参数的退化损伤是高剂量率条件下的2.46-816.67倍,受试样品具有明显的增强型低剂量率敏感度效应(ELDRS),辐照敏感参数为输入偏置电流、输入失调电流、输入失调电压和开环增益,退化损伤结果与辐照剂量率、辐照偏置有关,高剂量率辐照后受试样品的室温退火有较小的时变效应,低剂量率辐照后受试样品的室温退火有明显的时变效应。

NPN双极晶体管的ELDRS效应及退火行为

对国产NPN双极晶体管在不同剂量率下的辐射效应和退火特性进行了研究。结果显示:在不同剂量率辐照下,NPN晶体管的特性衰降均非常明显。不仅晶体管的过剩基极电流明显增大,直流增益迅速下降,其集电极电流也随辐照总剂量的增加而逐渐衰减,且低剂量率辐照下损伤更明显。本中对造成各种实验现象的损伤机理进行了分析。

国产pnp双极晶体管在宽总剂量范围辐照下的ELDRS

研究了不同偏置条件下国产商用pnp型双极晶体管在宽总剂量范围内的辐射损伤特性和变化规律。实验结果表明,在100 rad（Si）/s和0.01 rad（Si）/s剂量率辐照下,总累计剂量达到200 krad（Si）时,这一宽总剂量范围内辐射损伤趋势均随着总剂量值不断累积而增大,且并未出现饱和。相同剂量率辐照下,发射结施加反偏状态时国产商用pnp双极晶体管的过剩基极电流变化最大,正偏下最小,零偏介于二者之间。两款晶体管均表现出明显的低剂量率损伤增强效应（ELDRS）,且在反偏下ELDRS更显著。并对出现这一实验结果的损伤机理进行了探讨。

Effects of orientation of substrate on the enhanced low-dose-rate sensitivity (ELDRS) in NPN transistors

The radiation effects and annealing characteristics of two types of domestic NPN bipolar junction transistors, fabricated with different orientations, were investigated under different dose-rate irradiation. The experimental results show that both types of the NPN transistors exhibit remarkable Enhanced Low-Dose-Rate Sensitivity （ELDRS）. After irradiation at high or low dose rate, the excess base current of NPN transistors obviously increased, and the current gain would degrade rapidly. Moreover, the decrease of collector current was also observed. The NPN transistor with （111} orientation was more sensitive to ionizing radiation than that with （100} orientation. The underlying mechanisms of various experimental phenomena are discussed in detail in this paper.

ELDRS and dose-rate dependence of vertical NPN transistor

The enhanced low-dose-rate sensitivity （ELDRS） and dose-rate dependence of vertical NPN transistors are investigated in this article. The results show that the vertical NPN transistors exhibit more degradation at low dose rate, and that this degradation is attributed to the increase on base current. The oxide trapped positive charge near the SiO2-Si interface and interface traps at the interface can contribute to the increase on base current and the two-stage hydrogen mechanism associated with space charge effect can well explain the experimental results.

12位双极数模转换器高低剂量率的辐射效应

通过对12位双极数模转换器在60Coγ射线的高低剂量率的辐照实验和室温退火实验的对比分析,发现数模混合电路在不同剂量率辐照下的电离辐照响应有很大差异。这种混合电路不但表现出明显的低剂量率损伤增强效应,而且表现出时间相关效应。结合辐射响应测试过程和空间电荷模型,对其损伤模块和辐射损伤机理进行初步探讨。

双极晶体管的高温变剂量率辐照效应

研究了双极晶体管的变剂量率电离辐射损伤,发现从高到低的变剂量率辐照更有利于低剂量率辐射损伤增强效应的加速评估。

不同类型双极晶体管的低剂量率辐射损伤增强效应损伤机制

文章研究了双极晶体管不同温度的低剂量率辐射损伤增强效应,发现NPN晶体管与PNP晶体管的低剂量率辐射损伤机制是不相同的.最后文章讨论了其中可能的内在机制。

不同偏置下10位双极模数转换器高低剂量率的辐射效应

研究了10位双极模数转换器(ADC)在60Coγ射线不同剂量率、不同偏置条件辐照下的电离辐射效应及退火特性。研究结果发现,此类模数混合信号电路在不同偏置和不同剂量率辐照下的电离辐照响应有较大差异。同一电参数既表现出低剂量率损伤增强效应(ELDRS)又表现出时间相关效应(TDE)。研究结果进一步表明,低剂量率辐照0 V偏置是最劣偏置;与之相反,高剂量率辐照5 V偏置是最劣偏置,而加电阻偏置对辐照损伤有一定的抑制作用。最后,结合空间电荷模型和边缘电场效应对其辐照损伤差异及退火机理进行了初步探讨。

Effect of ionizing radiation on dual 8-bit analog-to-digital converters (AD9058) with various dose rates and bias conditions

The radiation effects on several properties （reference voltage, digital output logic voltage, and supply current） of dual 8-bit analog-to-digital （A/D） converters （AD9058） under various biased conditions are investigated in this paper. Gamma ray and 10-MeV proton irradiation are selected for a detailed evaluation and comparison. Based on the measurement results induced by the gamma ray with various dose rates, the devices exhibit enhanced low dose rate sensitivity （ELDRS） under zero and working bias conditions. Meanwhile, it is obvious that the ELDRS is more severe under the working bias condition than under the zero bias condition. The degradation of AD9058 does not display obvious ELDRS during 10-MeV proton irradiation with the selected flux.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied, as an accelerated enhanced low dose rate sensitivity （ELDRS） test technique, are investigated in terms of a specially designed gate-controlled lateral PNP transistor （GLPNP） that used to extract the interface traps （Nit） and oxide trapped charges （Not）. Electrical characteristics in GLPNP transistors induced by 60Co gamma irradiation are measured in situ as a function of total dose, showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP. Based on the analysis of the variations of Nit and Not, with switching the temperature, the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation. Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup. In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP, which provides us with a new insight into the test technique for ELDRS.

Dose-rate effects of p-channel metal oxide semiconductor field-effect transistors at various biasing conditions

The total-dose response and annealing effect of p-channel metal oxide semiconductor field-effect transistors （PMOSFETs） were investigated at various dose rates and biasing conditions.The results show that the shift of threshold voltage is more obvious when the dose rate is decreased.Under the various dose rates and biasing conditions,some have exhibited a time-dependent effect and others showed enhanced low-dose-rate sensitivity（ELDRS）.Finally,using the subthreshold-separating method,the threshold-voltage shift is separated into shifts due to interface states and oxidetrapped charges,and the underlying mechanisms of the observed effects are discussed.It has been indicated that the ELDRS effect results from the different quantities of the interface states generated at high and low dose rates.

Non-equilibrium carrier capture,recombination and annealing in thick insulators and their impact on radiation hardness

This paper describes an approach to prediction of the thick insulators＇ radiation response based on modeling of the charge yield, which is dependent on irradiation temperature, dose rate, and electric field magnitudes. Temperature behavior of the charge yield and degradation saturation due to the interface precursor depletion has been modeled and simulated. Competition between the time-dependent and true dose rate （ELDRS） effects has been simulated and discussed within a framework of the rate-equation-based mathematical model. It was shown that the precursor trap in the thick insulating oxides can be important at high dose rates. It was also shown that full filling of the shallow hole traps in the insulating oxide bulk can cause suppression of dose-rate sensitivity at relatively high dose rates, especially in thick insulators.

Total ionizing dose effects of domestic Si Ge HBTs under different dose rates

The total ionizing radiation（TID） response of commercial NPN silicon germanium hetero-junction bipolar transistors（Si Ge HBTs） produced domestically are investigated under dose rates of 800 m Gy（Si）/s and 1.3 m Gy（Si）/s with a Co-60 gamma irradiation source. The changes of transistor parameters such as Gummel characteristics, and excess base current before and after irradiation, are examined. The results of the experiments show that for the KT1151, the radiation damage is slightly different under the different dose rates after prolonged annealing, and shows a time dependent effect（TDE）. For the KT9041, however, the degradations of low dose rate irradiation is higher than for the high dose rate, demonstrating that there is a potential enhanced low dose rate sensitivity（ELDRS） effect for the KT9041. The possible underlying physical mechanisms of the different dose rates responses induced by the gamma rays are discussed.

Study of the dose rate effect of 180 nm nMOSFETs

Radiation induced offstate leakage in the shallow trench isolation regions of SIMC 0.18 μm nMOSFETs is studied as a function of dose rate. A ＂true＂ dose rate effect （TDRE） is observed. Increased damage is observed at low dose rate （LDR） than at high dose rate （HDR） when annealing is taken into account. A new method of simulating radiation induced degradation in shallow trench isolation （STI） is presented. A comparison of radiation induced offstate leakage current in test nMOSFETs between total dose irradiation experiments and simulation results exhibits excellent agreement. The investigation results imply that the enhancement of the leakage current may be worse for the dose rate encountered in the environment of space.

The enhanced low dose rate sensitivity of a linear voltage regulator with different biases

A linear voltage regulator was irradiated by ^（60）Coγat high and low dose rates with two bias conditions to investigate the dose rate effect.The devices exhibit enhanced low dose rate sensitivity（ELDRS） under both biases. Comparing the enhancement factors between zero and working biases,it was found that the ELDRS is more severe under zero bias conditions.This confirms that the ELDRS is related to the low electric field in a bipolar structure. The reasons for the change in the line regulation and the maximum drive current were analyzed by combining the principle of linear voltage regulator with irradiation response of the transistors and error amplifier in the regulator. This may be helpful for designing radiation hardened devices.