ZrO2 seed layer effects on switching characteristics and low-frequency noise in HZO ferroelectric tunnel junction arrays

Abstract

Ferroelectric tunnel junctions (FTJs) based on Hf<inf>0.5</inf>Zr<inf>0.5</inf>O<inf>2</inf> are promising devices for in-memory and neuromorphic computing, but their performance and reliability are often limited by defect-induced instabilities and electrical noise. In this work, we investigate the effect of ZrO<inf>2</inf> seed layer engineering on the switching and low-frequency noise (LFN) characteristics of 48 × 48 FTJ arrays. The insertion of ZrO<inf>2</inf> seed layers enhances ferroelectric polarization, widens the memory window, and improves cycling endurance and retention. LFN spectroscopy reveals that seed layers effectively suppress 1/f fluctuations by reducing active trap density and stabilizing conduction pathways. The noise exponent γ shows smaller variations after cycling in seed-layered devices, indicating suppressed defect migration and improved reliability against wake-up and fatigue. Furthermore, system-level evaluation confirms that the experimentally observed noise levels have negligible influence on neuromorphic inference accuracy, with seed-layered devices exhibiting reduced accuracy variation. These findings demonstrate that interface engineering with ZrO<inf>2</inf> seed layers provides a practical route to improving the electrical stability and noise robustness of HZO-based FTJs, ensuring reliable operation for advanced memory and computing applications.