On the profile of frequency dependent series resistance and dielectric constant in MIS structure

Abstract

In this study, the frequency dependent of the forward and reverse bias capacitance–voltage ( C– V) and conductance–voltage ( G/ ω – V) measurements of Al/SiO 2/p-Si (MIS) structures are carried out in frequency range of 10 kHz–10 MHz. The frequency dependence of series resistance ( R s), density of surface states ( N ss), dielectric constant ( ε′), dielectric loss ( ε″), dielectric loss tangent (tan δ) and the ac electrical conductivity ( σ dc) are studied for these structure at room temperature. Experimental results show that both electrical and dielectric parameters were strongly frequency and voltage dependent. The ε′ and ε″ are found to decrease with increasing frequency while σ ac is increased. Also, both the effects of surface states N ss and R s on C– V and G/ ω – V characteristics are investigated. It has been seen that the measured C and G decrease with increasing frequency due to a continuous distribution of N ss in frequency range of 10 kHz–1 MHz. The effect of R s on the C and G are found noticeable at high frequencies. Therefore, the high frequencies C and G values measured under both reverse and forward bias were corrected for the effect of series resistance R s to obtain real MIS capacitance C c and conductance G c using the Nicollian and Goetzberger technique. The distribution profile of R s– V gives a peak in the depletion region at low frequencies and disappears with increasing frequencies.