Temperature-dependent analysis of charge carrier current in Al/SiO2/p-type Si MOS structures with TiN-induced traps via the Poole-Frenkel conduction mechanism using the vertical optimization method

Abstract

In this study, we examined the Al/SiO2/p-type Si metal/oxide/semiconductor (MOS) structure across a temperature range of 303–423 K. To create intentional traps in the oxide, a 20 nm TiN layer was deposited. We analyzed the charge carrier current as a function of temperature using the Poole-Frenkel (PF) current mechanism and simultaneously extracted the five parameters (φ, Nh/e, µ, εr, and Vcorr) characterizing the PF current conduction process through the vertical optimization method (VOM), without the need for capacitance-voltage measurements or additional graphical methods. The barrier φ decreased with increasing temperature in both accumulation and inversion modes, with slopes of dφ/dT =−1.16 meV/K and−0.833 meV/K and intercepts of 3.07 eV and 3.45 eV, respectively. Carrier densities (Nh, Ne) also decreased as temperature rose, ranging from 7×1018–5×1010 cm−3 in accumulation mode and 6.5×1018–7.98×1016 cm−3 in inversion mode, indicating a more pronounced PF current mechanism in accumulation mode. Hole mobility (µh) remained significant up to 363 K but decreased sharply at higher temperatures, whereas electron mobility (µe) remained higher. The relative permittivity εr decreased with increasing temperature, indicating greater SiO2 polarization at lower temperatures. The voltage correction Vcorr varied with temperature, decreasing in accumulation mode by 1 Vcorr−acc = −1.33 V and increasing in inversion mode by 1 Vcorr−inv = 1.03 V. The oxide voltage correction at T = 0 K was found to be 2.606 V for holes (in accumulation) and −2.302 V for electrons (in inversion). The study concludes that trapping and detrapping mechanisms are more significant for holes in accumulation mode than for electrons in inversion mode. Consequently, the p-type MOS with PF leakage current is unsuitable for technological applications, while the n-type MOS shows promise, even at elevated temperatures, due to the less pronounced PF current mechanism.