Test structure for determining the charge distribution in the oxide of MOS structure

We propose a measurement method to obtain the charge distribution in the oxide layer of a MOS structure. We obtain various oxide thicknesses by gradually varying the etching time of the oxide layer (slanted etching). Using this method, we have determined the charge distribution in the oxide layer of MOS structures before and after ammonia annealing by measuring the mid-gap voltages of C-V curves.