The Role of Tunneling Oxide in the Low Frequency Noise of Multi-level Silicon Nitride ReRAMs

TL;DR

This study investigates how tunneling oxide influences low-frequency noise in multi-level silicon nitride RRAMs, revealing that resistance changes are mainly due to nitrogen vacancy variations affecting conductive filaments.

Contribution

It provides new insights into the role of tunneling oxide and nitrogen vacancies in multilevel resistance switching in silicon nitride RRAMs.

Findings

High resistance states are governed by nitrogen vacancy variations.

Tunneling oxide does not degrade filament interface quality.

LFN analysis links resistance states to filament conductivity modulation.

Abstract

This research explores the characteristics of two CMOS-compatible RRAM cells utilizing silicon nitride as the switching material. By employing SET/RESET pulse sequences, the study successfully attains four distinct and stable resistance states. To gain deeper insights, a Low-Frequency Noise (LFN) statistical analysis is conducted to investigate the role of a tunneling oxide between the bottom electrode and SiNx at various resistance levels. The findings from the LFN measurements strongly suggest that the multilevel high resistance switching primarily arises from variations in the number of nitrogen vacancies, which in turn modulate the conductivity of conductive filaments (CF). Notably, this modulation does not compromise the quality of the filament's surrounding interface. This research sheds light on the underlying mechanisms of RRAM cells and their potential for advanced memory applications.