First-principles study on non-radiative carrier captures of point defects associated with proton generation in silica

Yunliang Yue,Xu Zuo,Yu Song,Xiao Liu,Haoran Zhu

doi:10.1063/5.0033421

Abstract

The non-radiative carrier captures of point defects associated with proton generation in both crystalline (α-quartz) and amorphous silica (a-SiO2) have been investigated by using first-principles calculations based on the density functional theory. Major point defects related to proton generation are considered, including the dimer and puckered configuration of oxygen vacancy, doubly hydrogenated oxygen vacancy, and hydroxyl E′ center. The carrier capture cross sections of the defects are calculated in terms of a one-dimensional static coupling method. The neutral dimer and doubly hydrogenated oxygen vacancies show a large hole capture cross section, and the positively charged puckered oxygen vacancy and the hydroxyl E′ center show a large electron capture cross section. These results further support that dissociation of molecular hydrogen at a positively charged dimer oxygen vacancy and that of a positively charged doubly hydrogenated oxygen vacancy are the main reactions in silica to generate protons that play a key role in ionization damage of silicon devices.

Highlights

IntroductionInterfacial traps in Si/a-SiO2 (amorphous SiO2) are related to the reliability issues of silicon microelectronics. In general, it is accepted that protons play a key role in the buildup of interfacetrap charge. Protons directly participate in the depassivation reactions of interface traps
Interfacial traps in Si/a-SiO2 are related to the reliability issues of silicon microelectronics.1 In general, it is accepted that protons play a key role in the buildup of interfacetrap charge.2,3 Protons directly participate in the depassivation reactions of interface traps
Positively charged hydroxyl E′ centers can generate protons with a very low reaction barrier, and they are suspected as major sources of proton in wet a-SiO2.10,11 It is obvious that all the proton-release reactions start with positively charged defects that result from hole capture processes

Summary

Introduction

Interfacial traps in Si/a-SiO2 (amorphous SiO2) are related to the reliability issues of silicon microelectronics. In general, it is accepted that protons play a key role in the buildup of interfacetrap charge. Protons directly participate in the depassivation reactions of interface traps. When hydrogen molecules are plenty, protons are mainly generated by cracking hydrogen molecules at positively charged oxygen vacancies.. When hydrogen molecules are plenty, protons are mainly generated by cracking hydrogen molecules at positively charged oxygen vacancies.4,5 Otherwise, they are generated by the dissociation of positively charged hydrogenated oxygen vacancies.. Oxygen vacancies prevail among defects in SiO2, while they may exhibit a number of configurations.7,8 Both dimer and puckered configurations of positively charged oxygen vacancies can react with hydrogen molecules to generate protons.. Charged doubly hydrogenated oxygen vacancies show a relatively low reaction barrier to dissociate.. Positively charged hydroxyl E′ centers can generate protons with a very low reaction barrier, and they are suspected as major sources of proton in wet a-SiO2.10,11 It is obvious that all the proton-release reactions start with positively charged defects that result from hole capture processes. The carrier capture processes of those defects have been poorly understood in the sense of first-principles calculations

Methods

Results

Conclusion