Basic Mechanisms of Radiation Effects in Heterostructure Devices

Oregon State University, Corvallis OR

Investigators

Abstract

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.