Electric and dielectric characteristics of Al/ZrO2/IL/n-Si MOS capacitors using three-frequency correction method

In this study, MOS capacitors of Al/ZrO2/IL/n-Si (IL: interface layer) have been fabricated. Bias scan and frequency scan data of measured parallel capacitance (C-m) and parallel resistance (R-m) have been taken in the frequency of similar to 1 kHz to 2 MHz. To correct external frequency dispersion of parasitic parameters, we have used five-element model (including MOS capacitance C, parallel resistance R-p, IL capacitance C-i, IL resistance R-i, and series resistance R-s) and three-frequency correction method. Extracted capacitance C by the three-frequency correction method has negligible frequency dependence from 0.38 nF to 0.34 nF in the average frequency of similar to 3.7 kHz to 1.54 MHz. The frequency dispersion of R-p, C-i, R-i, and R-s are explained by some physical mechanisms. Small relative errors Delta C/C, Delta R-p/R-p, Delta C-i/C-i, Delta R-i/R-i and Delta R-s/R-s are less than 0.2%, 2%, 3%, 1.2% and 0.4% respectively. We have also used two existing double-frequency methods of three- and four-element models for comparison, and the extracted capacitances show abnormal frequency dependence. Above results indicate the three-frequency method of five-element model is necessary, effective and convenient in providing sufficient list data for bias voltage dependence or frequency dependence. The dielectric parameters, such as relative dielectric constant, conductivity, imaginary part of complex dielectric constant, and dielectric loss tangent have been calculated. The mechanisms of frequency dispersion for the dielectric parameters have been analyzed.