Channel length effect in a MOSFET structure by scanning capacitance microscopy

Depth dependent carrier density and trapped charges in a metal-oxide-semiconductor field effect transistor (MOSFET) like structure have been studied using scanning capacitance microscopy (SCM). For a MOSFET structure, since minority carrier can be provided by the source and drain diffusions, its response time is shorter than that of metal-oxide-semiconductor (MOS) system. So the high frequency C–V relation is slightly different from that of MOS capacitor and shows the characteristics dependent on the channel length. Bias dependent SCM images which represent the depth dependent carrier density and detrapping time constant of trapped charges in the oxide layer were observed to see the channel effect in a MOSFET structure.