STUDY OF THE OXIDE TRAPS AND INTERFACIAL STATES AT THE Si-SiO2 INTERFACE BY VUV IRRADIATION.

The authors study the oxide traps and Si-SiO//2 interfacial states introduced in MOS samples with n (100) silicon substrate by VUV irradiation (Helium discharge source). Experimental evidence indicates that hole traps with density in the order of 10**1**2/cm**2 exist in both the ″Wet″ and ″Dry″ oxides, and that the acceptor like electron traps with density in the order of 10**1**1/cm**2 exist in part of these oxides. A broad peak of interfacial states density with definite energy level appears in the ″Wet″ oxide samples under irradiation with positive or zero gate bias. The density of interfacial states depends upon the hole trapping process. In the range of 1 multiplied by 10**1**0 to 5 multiplied by 10**1**1 cm** minus **2 multiplied by (times) ev** minus **1, the midgap density of interfacial states is proportional to the density of holes trapped. Interfacial states introduced by irradiation cannot be annihilated by injecting electrons. Results are explained by a hole trapping-weak bonds breaking model.