Numerical modeling of defect states in SOI MOSFET devices

Recently, a great deal of interest has developed in silicon-on-insulator metal oxide semiconductor field effect transistor structures using polycrystalline silicon for the channel region. Applications varying from thin-film transistors for display and detector technologies to transistors for active loads in static random access memory cells are under investigation. The polycrystalline silicon used in these structures has defects, however, due to its inherent grain/grain boundary composition and, often, due also to the fabrication processing used. Additionally, ionizing radiation present during processing or operation can influence device performance through changes induced in the insulating substrate of these devices. The effect of defects as function of type, spatial location, and energetic location on device performance are investigated. This is accomplished through the use of a numerical model which solves the potential equation and the electron continuity equation within the device.