Basic Mechanisms of Radiation Effects in Heterostructure Devices

随着为军事和商业空间应用而发射的卫星数量迅速增加，半导体器件的辐射可靠性是一个重要的关注领域。考虑到发射和维护卫星基地资源的高成本，仔细考虑卫星上复杂电子系统的可靠性是非常重要的。同样，所有的电子系统，特别是用于核反应堆和武器环境的安全设备，即使在意外暴露于中子爆炸的情况下也必须可靠地运行。硅器件中的辐射效应已经得到了广泛的研究。相比之下，目前对基于III-V化合物半导体（例如GaAs）的异质结构器件的辐射效应的了解非常有限。众所周知，这些器件在更高的速度/频率下比传统的硅器件表现出更优越的性能。因此，越来越多的GaAs和相关的III-V化合物半导体器件被用于基于卫星的高速通信系统。本项目的目的是研究两种重要异质结构器件的辐射效应：(a)高电子迁移率晶体管（HEMTs）和(b)异质结双极晶体管（HBTs）。这两种器件广泛应用于许多GaAs射频电路和高速数字集成电路中。本研究将使用下列三种不同类型的辐射源：(1)质子；(2)电子；(3)中子。关于上述类型的辐射对有关装置的影响，我们目前的知识状况，以及将要进行的工作的具体细节，将在建议的主体部分讨论。本项目的主要研究内容包括：1、对器件不同层的辐射致缺陷特性和器件（hemt和HBTs）在不同类型辐射下的性能退化进行实验研究。o对辐射引起的缺陷的特征、基本机制和器件性能退化之间的关系有系统的了解。o在了解器件结构组成材料的辐射诱发缺陷的情况下，为器件在实际辐射环境下的退化发展一个完整的预测模型。这项研究计划的一个主要影响将是开发新的设备/电路设计，以提高抗辐射影响的可靠性。该计划还将培养具有设计、制造和分析辐射环境中应用的先进异质结构器件的专业技能的新一代设备工程师。这有望产生具有改进辐射可靠性的先进III-V化合物半导体器件。

Radiation reliability of semiconductor devices is an important area of concern with the rapid growth in the number of satellites launched for military and commercial space-applications. Given the high cost of launching and maintaining a satellite-base resource, it is very important to give a careful consideration of the reliability of the sophisticated electronic systems on board the satellite. Similarly, all the electronic systems, especially the safety equipment used in nuclear reactor and weapon environment must operate reliably even in the case of an accidental exposure of the equipment to a burst of neutrons.Radiation effects in silicon devices have been studied extensively. In comparison, the current knowledge of radiation effects in III-V compound semiconductor (e.g. GaAs) based heterostructure devices is very limited. It is well known that these devices exhibit superior performance especially at higher speeds/frequencies than the conventional silicon devices. Hence, increasing numbers of GaAs and related III-V compound semiconductor devices are being used in satellite-based high speed communication systems.The objective of this project is to conduct research on the radiation effects in two important types of heterostructure devices: (a) High Electron Mobility Transistors (HEMTs) and (b) Heterojunction Bipolar Transistors (HBTs). Both types of devices are extensively used in a number of GaAs RF circuits and high-speed digital integrated circuits. The following three different types of radiation sources will be used in this investigation: (1) protons (2) electrons and (3) neutrons. The current status of our knowledge on the effects of the above types of radiation on the devices of interest and the specific details of the work to be conducted are discussed in the main body of the proposal.Some key elements of research issues addressed in this program are:o Conduct experimental investigations of the characterization of the radiation-induced defects in the different layers of the device and the performance degradation of the devices (HEMTs and HBTs) under different types of radiation.o Develop a systematic understanding of the relationship between the characteristics of radiation-induced defects, the basic mechanisms and degradation of the performance of the devices.o Develop a complete model for the prediction of device degradation in actual radiation environment given the knowledge of the radiation-induced defects in the constituent materials of the device structure.A major impact of this research plan will be on the development of new device/circuit designs for greater reliability against radiation effects. The proposed program will also educate a new generation of device engineers with specialized skills in the design, fabrication and analysis of advanced heterostructure devices meant for applications in radiation environment. This is expected to result in advanced III-V compound semiconductor devices with improved radiation reliability.