双极晶体管电离和位移协同效应特征及机理研究

Bipolar junction transistors (BJTs), as important electronic components in analog or mixed-signal integrated circuits (ICs) and BiCMOS (Bipolar Complementary Metal Oxide Semiconductor) circuits, are employed for spacecrafts. BJTs are sensitive to both displacement and ionization damage. Therefore, the research on characteristics and mechanisms of synergistic effect of ionization with displacement damage in the BJTs caused by combined radiation of protons and electrons has very important significance and worthiness. Up to now, there are lots of researches on either ionization or displacement effects induced by single irradiation sources for BJTs, while few references are available on the interaction between the ionization and displacement effects in BJTs, which are produced by combined radiation of protons and electrons. This situation limits an insight into the radiation damage mechanisms for BJTs under space radiation environment, and also makes against to characterize the degradation of electrical parameters on orbit clearly. Based on the combined irradiation of protons and electrons with lower energies, this project will discover basic characteristics and propose a damage physical model for the synergistic effect of ionization with displacement damage in both the NPN and PNP transistors, by means of three approaches, including the degradation characterization of electrical parameters, the annealing analysis after irradiation and the deep level transient spectroscopy. The obtained results could give a theoretic basis to optimize the resistant ability to radiation and to evaluate the degradation in electrical parameters on orbit for the BJTs.

双极晶体管是航天器上广泛应用的重要电子器件，在模拟或混合集成电路及BiCMOS电路中有着重要的作用。双极晶体管对电离和位移效应均较为敏感，深入研究其在质子和电子综合作用下产生电离和位移协同效应的特征与机理具有重要的理论和实际意义。迄今，国内外主要在单因素辐照下研究双极晶体管的电离效应和位移效应，而对质子和电子综合辐照时电离效应和位移效应之间的交互作用研究较少。这在很大程度上限制了人们对双极晶体管辐射损伤机理的认识，也不利于对其在空间辐射环境下性能退化进行量化表征。本项目拟在低能质子和电子综合辐照的基础上，基于电性能退化表征、辐照后退火效应分析及深能级瞬态谱测试三种途径，揭示NPN型及PNP型晶体管产生电离和位移协同效应的基本特征与机理，建立双极晶体管电离和位移协同效应损伤物理模型。所得研究结果可为双极器件抗辐射性能优化及在轨电性能退化评价提供理论依据。

双极晶体管是航天器上广泛应用的重要电子器件，在模拟或混合集成电路及 BiCMOS 电路中有着重要的作用。双极晶体管对电离和位移效应均较为敏感，深入研究其在质子和电子综合作用下产生电离和位移协同效应的特征与机理具有重要的理论和实际意义。本项目以双极晶体管为研究对象，选取电子、质子、Co-60 射线及重离子作为辐照源，研究了双极晶体管电离效应、位移效应及其协合效应的特点和电性能退化规律。基于电性能退化表征、辐照后退火效应分析及深能级瞬态谱测试三种途径，揭示NPN型及PNP型晶体管产生电离和位移协同效应的基本特征与机理。所得研究结果可为双极器件抗辐射性能优化及在轨电性能退化评价提供理论依据。.研究结果表明，不同种类的辐照源辐照时，NPN和PNP型双极晶体管的电性能参数呈现类似的变化趋势，器件类型对电性能参数变化趋势的影响不大。电离辐射损伤条件下，双极晶体管的电性能参数退化随辐照注量逐渐趋于饱和。基于深能级瞬态谱(DLTS)分析结果可知，电离辐射损伤会在双极晶体管集电区产生类深能级缺陷信号，在NPN型晶体管集电区表现为多子俘获陷阱，在PNP型晶体管集电区表现为少子俘获陷阱。位移和电离/位移协合辐射损伤时，双极晶体管的电性能随辐照注量持续退化，未见饱和趋势。位移辐射损伤在双极晶体管集电区中产生的深能级缺陷以多子俘获陷阱为主。.重离子或低能质子与低能电子的综合辐照试验表明，双极晶体管电离损伤对位移损伤起退火和加剧两种作用机制。DLTS测试结果表明，当低能电子辐照注量较小时，有利于低能电子产生的电离损伤使重离子位移辐射缺陷信号部分恢复，导致双极晶体管的电流增益逐渐恢复；当低能电子注量较大时，低能电子电离辐射损伤效应增强，促进重离子位移辐射缺陷浓度明显增加和电流增益衰降。.在等时退火过程中，经不同类型粒子辐照后的晶体管电性能参数随着退火温度的升高均逐渐恢复。当退火温度达到700K时，NPN和PNP型双极晶体管的电性能参数均可恢复至辐照前的水平。随着退火温度的升高，电离辐射损伤缺陷浓度逐渐降低。对于位移辐射损伤，退火温度较低时(<550K)，随着退火温度的升高，能级较深的缺陷浓度逐渐降低，而能级较浅的缺陷浓度逐渐升高；退火温度较高时(>550K)，随退火温度的升高，辐照缺陷浓度均逐渐降低。