Electron trap level of hydrogen incorporated nitrogen vacancies in silicon nitride

Abstract

Hydrogen incorporation into nitrogen vacancies in silicon nitride and its effects on electron trap level are analyzed using simulation based on density functional theory with temperature- and pressure-dependent hydrogen chemical potential. If the silicon dangling bonds around a nitrogen vacancy are well separated each other, hydrogen incorporation is energetically stable up to 900 °C, which is in agreement with the experimentally observed desorption temperature. On the other hand, if the dangling bonds strongly interact, the incorporation is energetically unfavorable even at room temperature because of steric hindrance. An electron trap level caused by a nitrogen vacancy becomes shallow by the hydrogen incorporation. An electron is trapped in a deep level created by a silicon dangling bond before hydrogen incorporation, whereas it is trapped in a shallow level created by an anti-bonding state of a silicon-silicon bond after hydrogen incorporation. The simulation results qualitatively explain the experiment, in which reduced hydrogen content in silicon nitride shows superior charge retention characteristics.

Experimental evidence of trap level modulation in silicon nitride thin films by hydrogen annealing

“…On the other hand, the shallower electron trap with ∼0.6 eV is generated when a hydrogen atom is induced outside a vacancy (called the "puckered defect" in Ref. 27). The electron traps observed in samples A and B are identified as puckered defects.…”

“…In previous studies, the incorporation of hydrogen atoms into nitrogen vacancies and its effect on electron trap level are analyzed by simulation. [27][28][29][30][31] To consider the relationship between the defect structure and trap level estimated in this study, the defect types and trap levels obtained from a previous calculation study 27) are displayed in Fig. 13.…”

A New 1P1R Image Sensor with In-Memory Computing Properties Based on Silicon Nitride Devices

“…SONOS, BiCS). The reason for this success is the presence of intrinsic bulk defects, acting as trapping levels for both electrons and holes [14]- [16].…”

Metal-Insulator-Metal Single Electron Transistors with Tunnel Barriers Prepared by Atomic Layer Deposition

“…Silicon nitride is known as a trap-rich material where the abundance of traps is generally associated with silicon atoms replacing nitrogen atoms, resulting in silicon dangling bonds, referred to as K-center defects [50]. Other defects can be associated with hydrogen, which is typically present in the SiNx matrix [51].…”