DETERMINATION OF INTERFACE TRAP DENSITY IN UNIPOLAR STRUCTURES USING QUASISTATIC C-V METHOD
Pavol Písečný - Milan Ťapajna - Ladislav Harmatha - Andrej Vrbický
The design and realization of computer controlled measurement for determination of the trap density
on the insulator-semiconductor interface
(Dit) using quasistatic C-V method is described. This method is simple, nevertheless, it
is the most accurate
technique for Dit determination in comparison to other ones. Using appropriate theoretical analysis, one can
also obtain the energy distribution of interface trap
density in the bandgap. In the experiment, two series of samples were used: (1) high-quality MOS structures prepared
by different oxidation processes
and (2) samples irradiated by 305MeV Kr+ and 710MeV Bi+ ions with different fluencies.
From pulsed MOS capacitor measurement (the so-called
C-t technique), surface generation velocity Sg was evaluated and, subsequently, the interface
capture cross-section was calculated. All the
results are discussed with regard to the amount of interface defects as well as their electrical activity.
Keywords: MIS structure, quasistatic C-V measurement, interface trap density