Effect of DC Stress on Low-Frequency Noise Characteristics of W-Doped In2O3 BEOL Transistors

Abstract

In this article, we perform the low-frequency noise (LFN) characterization of back-end-of-line (BEOL) compatible transistors. Specifically, the noise performance of oxide channel (W-doped In2O3, or IWO) transistors with a dielectric gate (IWOMOSFET) and ferroelectric gate (IWO FeFET) is studied and compared. The objective of this study is to understand the impact of a ferroelectric gate on the device reliability under dc stress. The normalized noise power spectral density ( ${S}_{I}/{I}_{D}^{\,{2}}$ ) value is extracted for a fresh device and stressed device. We find that a ferroelectric gate-stack induces $3\times $ more noise than a dielectric gate-stack. Further, the increase in post stress ${S}_{I}/{I}_{D}^{\,{2}}$ for IWO FeFET is $7.5\times $ higher than that for IWO MOSFET under positive stress voltage, and negligible for both devices under negative stress voltage. We conclude that the stress induced by the same gate voltage in IWO FeFET is higher than that in IWO MOSFET is due to the electric field enhancement caused by polarization in the ferroelectric gate-stack, which leads to more defect generation under the stress.