Comparison of interface trap density measured by capacitance/subthreshold/charge-pumping methods for n-MOSFETs with Si-implanted gate-SiO/sub 2/

Effects of channel B-implantation before gate oxidation and heavy Si-implantation into the gate-SiO/sub 2/ on interface trap density D/sub it/ distribution in the energy gap for n-MOSFETs are analyzed by three different measurement methods: (I) high-low frequency capacitance, (II) subthreshold current, and (III) charge pumping. These three methods produce similar results for D/sub it/. They indicate that the channel B/sup +/-dose scarcely has any effect on D/sub it/ at midgap and increases as larger Si-doses give an increase in D/sub it/. Method I can provide the D/sub it/ distribution across the majority of the bandgap and may cause an underestimation of D/sub it/. Method II is convenient with reasonable accuracy due to the simple DC measurement.