Random telegraph noise of junction leakage current in submicron devices

A random telegraph noise in submicron metal-oxide-semiconductor field-effect transistors (MOSFETs) has been found, and the noise fluctuation is examined in detail to clarify the mechanism causing it. This fluctuation, named variable junction leakage (VJL), was observed in the leakage current that occurred at a p-n junction in MOSFETs. We measured the temperature and bias dependences of the VJL in detail, and measured some VJLs in samples fabricated with different process conditions. We found that the activation energy of the fluctuation amplitude in VJL varied from 0.3 to 0.7 eV among the samples and that the fluctuation amplitude of VJL increased as the electric field increased at a junction in a MOSFET. These results support the model that regards VJL as the dynamic fluctuation in Shockley-Read-Hall current or trap-assisted-tunneling current. We suggest the possibility that the origin of VJL is a fluctuation in the trap energy level or capture cross section of a defect. These results provide fresh insight into defects in silicon.