A detailed analysis of electrical parameters and energy dependence of interface Traps in Au-(Co:PVA)-nSi-Al structure via impedance measurements

In this study, impedance measurements of the Au-(Co:PVA)-nSi-Al structure were conducted across a frequency range of 1-1000 kHz and a voltage range of - 3.5 V to + 2 V. Following this, the voltage and frequency dependence of key electrical parameters including the density of donor atoms (ND), built-in voltage (qVbi), barrier height (Phi B), depletion layer width (WD), and maximum electric field (Em) were derived from the linear region of the 1/C2 versus V plots. The voltage-dependent density of interface traps (Nit) was determined using three distinct methods: high-low frequency capacitance, the Hill-Coleman, and parallel conductance methods. Additionally, the voltage-dependent series resistance (Rs) was extracted from the Nicollian-Brews model for each frequency. The experimental results revealed that nearly all fundamental electronic parameters exhibit significant variations with both frequency and voltage, particularly at low and intermediate frequencies. These variations are attributed to the specific distribution of Nit at the interlayer-semiconductor interface, their relaxation times (tau), the (Co:PVA) interlayer, and the Rs. To mitigate the influence of Rs on the high-frequency C/V and G/omega-V curves, corrections were applied at 1 MHz. It was observed that while Nit predominantly influences the inversion and depletion regimes at lower frequencies, the Rs becomes the dominant factor in the accumulation regime at higher frequencies.