Charging damage of silicon-on-insulator (SOI) wafer determined by scanningMaxwell-stress microscopy

Charging damage of silicon-on-insulator (SOI) wafer induced by electron-bea m (EB) lithography and reactive ion etching (RIE) has been investigated in terms of the surface potential change through the processes. Scanning Maxwe ll-stress microscopy (SMM) was utilized for measuring the SOI surface poten tial under a floating condition. Surface contamination due to resist residu es was clearly observed in the SMM potential image. Negative charging of th e SOI islands induced by EB lithography was observed particularly under an excessive EB exposure condition and conserved for several days. The cause o f the negative charging is considered to be the trapping of electrons in th e buried oxide of the SOI wafer.