不同偏置条件下基区掺杂浓度对NPN双极晶体管电离辐照的影响

对相同工艺制作但基区掺杂浓度不同的国产NPN双极晶体管,在不同偏置条件下进行60Co-γ辐照效应和退火特性研究.结果显示:基区掺杂浓度不同,NPN双极晶体管辐照响应也不相同,低基区掺杂浓度的晶体管辐照损伤要明显大于高基区掺杂浓度的晶体管辐照损伤;偏置条件不同,晶体管辐照响应也有很大差别,反向偏置辐照NPN晶体管参数退化...     

变温辐照加速评估方法在不同工艺的NPN双极晶体管上的应用

对6种不同工艺的NPN双极晶体管进行了高、低剂量率及变温辐照的~(60)Coγ辐照实验。结果显示,6种工艺的NPN双极晶体管均有显著的低剂量率辐照损伤增强效应。而变温辐照损伤不仅明显高于室温高剂量率的辐照损伤,且能很好地模拟并保守地评估不同工艺的NPN双极晶体管低剂量率的辐照损伤。对实验现象的机理进行了分析。     

不同偏置条件下NPN双极晶体管的电离辐照效应

对NPN双极晶体管进行了不同剂量率、不同偏置条件下的电离辐射实验。研究结果表明：同一剂量率辐照时,无论是低剂量率还是高剂量率,辐照损伤均是基-射结反向偏置时最大,零偏置次之,正偏置最小。NPN双极晶体管在3种偏置下均可观察到明显的低剂量率辐照损伤增强（ELDRS）效应,且偏置条件对ELDRS效应很明显,表现为基-射结正向偏置ELDRS效应最为显著,零偏次之,反向偏置最次。对出现这一实验结果的机理进行了探讨。     

工艺条件对双极晶体管低剂量率辐射损伤增强效应的影响

对具有相同制作工艺但NPN管的发射极面积不同以及LPNP管发射极掺杂浓度相异的两种不同类型的国产双极晶体管,在不同剂量率下进行辐射效应和退火特性研究。结果表明:晶体管类型不同,对高低剂量率的辐照响应也相异;不同发射极面积的NPN管的结果显示,发射极面积越小,损伤越大;不同掺杂浓度的LPNP管的结果则表明,轻掺杂的发射极比重掺杂的具有更高的辐射敏感性。对各种实验现象的损伤机理进行了较详细的分析。     

PNP输入双极运算放大器的辐射效应

对PNP输入双极运算放大器进行了不同偏置条件和不同剂量率下电离辐照实验。结果表明,高剂量率辐照时,正偏置条件下的偏置电流变化稍大于零偏置;低剂量率辐照时,正偏置下的偏置电流变化小于零偏置。两种PNP输入双极运算放大器均表现出明显的低剂量率辐照损伤增强（ELDRS）效应,且在零偏置下的低剂量率辐照损伤增强效应更显著。     

不同偏置条件的10位CMOS模数转换器的辐射效应

对10位CMOSADC7910在不同偏置条件下的电离辐射效应及退火特性进行了研究。结果表明:模数混合电路在不同偏置条件下的电离辐照响应有很大的差异。与加电偏置相比,零偏下0.25Gy/s(Si)剂量率辐照时的辐射损伤更严重。并对其损伤机理进行了初步探讨。     

双极晶体管不同剂量率的辐射效应和退火特性

不同类型和型号的国产及进口双极晶体管的不同剂量率的辐照效应及退火特性进行了研究。结果表明：在辐照的剂量率范围内,无论是国产还是进口的双极晶体管,都有明显的低剂量率辐照损伤增强现象,且NPN管比PNP管的明显。文中对引起双极器件辐照损伤差异的机理进行了探讨。     

东方百合组培芽增殖阶段60Coγ射线辐射效应研究

采用⁶⁰Coγ射线辐照东方百合鳞片,组培后以其诱导的不定芽进行增殖培养，对芽3次增殖过程中的辐射效应进行研究。试验结果表明，辐照明显影响芽的增殖，但随增殖次数的增加，芽增殖数和芽增殖率受辐照因素的影响明显降低。在第1次增殖期，辐照对芽增殖的影响表现为抑制作用，这种现象在高剂量辐照时表现得更加明显；在第3次增殖期，辐照对芽增殖的抑制作用已消失，但芽的生理状态仍处于损伤修复作用的末期。辐照剂量对不同培养基上接种不同部位鳞片产生的不定芽蛋白质、MDA含量有不同影响。     

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。     

AlteraSRAM型现场可编程门阵列总剂量辐射效应

通过比较不同模块的输出波形、不同源程序的功耗电流以及输出端口的高、低电平随总剂量的变化关系，研究了AlteraSRAM型现场可编程门阵列（FPGA）器件在⁶⁰Coγ源辐照下的总剂量辐射效应。实验结果表明：器件的功能和功耗电流随总剂量的变化不同；不同模块随总剂量的变化关系相似，不同源程序的功耗电流随总剂量的变化趋势一致；总剂量辐照实验时功耗电流可作为判断器件失效的1个敏感参数。     

Calculation of Electrical and Radiation Storage Time in Transistors

The conventional viewpoint of saturation in junction transistors, from a device point of view, considers the excess minority carriers in the base region. A different viewpoint considers the majority carriers in the base. The important elements then are the number of these carriers stored in the transistor and whether they are stored in the active base region, the extrinsic base region, the collector body, or the epitaxial layer. The storage of carriers in the active base region plays a relatively minor role in the storage effect for most modern transistors because of the small volume of semiconductor material involved. In alloy, diffused, and epitaxial transistors the storage of carriers (electrons in a PNP transistor) is shown to be in the last three regions named above, respectively; in none of these transistor types is the storage region identifiable as the active base region. This new viewpoint leads to well-accepted storage-time expressions for alloy and diffused transistors and to new storage-time expressions for epitaxial transistors. Detailed calculations of the primary photocurrent have been made for three practical transistor construction types that relate this current to basic device parameters and to the electrical storage time. In addition, the radiation storage time has been calculated in terms of the electrical storage time for epitaxial transistors. Examples of these calculations are given and the results presented.     

不同温度辐照下栅控双极晶体管的总剂量效应参数退化研究

本文选用特殊测试结构的栅控横向PNP(gated lateral PNP, GLPNP)双极晶体管为研究对象,在不同辐照温度下,得到了温度和剂量对GLPNP双极晶体管辐射损伤的响应机制。试验结果表明,温度和剂量是影响界面陷阱电荷生成和退火动态平衡的关键因素。在低剂量阶段,高温辐照会导致GLPNP双极晶体管辐射损伤加快,在高剂量阶段,适当降低温度会促进界面陷阱电荷的生长。     

Short-Term Annealing in Transistors Irradiated in the Biased-Off Mode

A set of experiments was performed at the White Sands Missile Range Fast-Burst Reactor Facility in which measurements were made of the annealing of three types of transistors (two NPN and one PNP) which were irradiated while biased off. Anneal factors as high as 5 or 6 were observed in the NPN devices when turned on tens of milliseconds after the neutron burst. The PNP device (2N2875) showed an anneal factor of nearly 4 when turned on 29 msec after the radiation pulse. The injection dependence of the annealing is clearly evident.     

Neutron Radiation Damage in Silicon Transistors

In the investigation of base and collector current as a function of the emitter-to-base voltage, previous studies have shown that neutroninduced base current has components originating in the emitter space charge region as well as the neutral base region. This study shows that while the low injection level neutron-induced base current is dominated by the space charge component, the high injection behavior appears to be controlled by recombination in the neutral base region. Additional experiments performed in special tetrode transistors and van der Pauw-type samples indicate that changes in collector current are dominated by recombination in the neutral base, while changes in base doping and mobility have only a secondary effect. These conclusions are reached from experiments on transistors with a ring emitter, on tetrode-type test transistors, and on special Hall-effect devices, and by a detailed analysis of the emission crowding characteristics of a "ring-dot" geometry device.     

Effect of Operating Conditions and Transistor Parameters on Gain Degradation

Data for predicting transistor gain degradation in a neutron radiation environment were obtained from experimental studies of the variation of the radiation damage constant KT as a function of temperature and current during both measurement and irradiation. Relatively small spreads in the values of KT were obtained when the individual base transit times were measured and the radiation exposures were precisely determined. Radiation damage effect data from 20 different n-p-n silicon transistor types were obtained and normalized to the same minority carrier concentration in the base region, using the transit time and the VBE-Ic characteristics of the specific transistors. The resulting relative dispersions of the damage constant for minority carrier densities of 1015/cm3 and 1016/cm3 were typically 15 to 20 percent. These dispersions indicate that electrical measurements of transistor physical parameters can provide reasonably accurate predictions of the gain degradation for a wide variety of transistors without additional radiation testing of specific transistor types.     

不同偏置对NPN双极晶体管的低剂量率电离辐照损伤的影响

对NPN双极晶体管进行了低剂量率下不同偏置条件的电离辐射实验。结果表明,不同偏置条件下的低剂量率辐射损伤具有明显差异。基-射结反向偏置时,其过剩基极电流最大,电流增益衰减最为显著。而基-射结正向偏置时,过剩基极电流和电流增益衰减都最小。讨论了出现这种结果的内在机制。     

Radiation Effects on Junction Field Effect Transistors

Experimentally determined permanent and transient effects of radiation on the electrical characteristics of junction field effect transistors (JFET's) are presented for JFET's exposed to energetic neutron doses up to 1016 neutrons/cm2 (E > 10 Kev) and ionizing radiation up to 8×109 rad/sec. Results of extensive transient radiation experiments using the AFCRL Linac are presented for various combinations of channel doping, gate resistor values, gate voltages, drain voltages, gold doping and dose rates. Limited new experimental data is presented on neutron damage. Existing neutron degradation data on hardened JFET's is summarized. The JFET neutron degradation theory is summarized and refined.     

Investigation of the Surface Ionization Effect on Planar Silicon Bipolar Transistors and the Improvement of the Resistance to Radiation by an Irradiation-Annealing Treatment

By irradiation of the surface structure of silicon planar transistors with a narrow electron beam adjusted parallel to the pn-junctions of the devices it was possible to show in a very direct manner that the increase in base current occurs only if the beam is directed to the immediate vicinity of the emitter-base pn-junction. Subjecting the collector-base pn-junction and the remainder of the transistor surface to radiation has no effect on the current gain. A comparison of the radiation damage to bipolar silicon planar transistors in metal packages and plastic envelopes shows that the packaging method has a strong influence on the degradation in current gain if the pn-junctions are reverse-biased during the irradiation. The resistance of bipolar planar transistors to ionizing radiation can be improved considerably if the device is subjected to a high dose of ionizing radiation under conditions at which the damage anneals out immediately. The cause for this phenomenon mainly is a decrease of the concentration of interface states effected by this treatment. Reductions of the increase in base/collector current ratio of one order of magnitude have been obtained.