Investigation of the total dose response of partially depleted SOI nMOSFETs using TCAD simulation and experiment

Abstract

We have analyzed total ionizing dose response of partially depleted SOI nMOSFETs fabricated in a 0.13μm commercial technology assisted by TCAD simulation. Using TCAD tools, the ionizing radiation-induced damages in buried oxide and shallow-trench oxide are investigated separately. It is shown that back transistors are radiation tolerant up to 1Mrad (Si) for core nMOSFETs even under the worst case whereas back transistors of I/O devices are 100krad (Si) due to lower doping concentration. In addition, the enhanced total dose degradation with applied gate bias is attributed to more charge trapped in shallow-trench oxide. 2D cross section electrical simulation schematically illustrates the evolution of charge trapping in buried oxide and shallow-trench oxide. It is found and verified that parasitic corner transistor located at the bottom of swallow-trench oxide plays a critical role on the radiation hardness of partially depleted SOI nMOSFETs.