Computational Study on Interfaces and Interface Defects of Amorphous Silica and Silicon

Abstract

The amorphous SiO2/Si interface is arguably the most important part in semiconductor technology, strongly influencing the device reliability. Its electronic structure is affected by the defects, majorly the dangling bonds known as Pb‐type defects, which have been studied for decades. These defects are usually passivated by hydrogen atoms in device processing, which eliminates the defect levels in the silicon bandgap and thus removes their electric activity. However, when the interface is exposed to ionization radiation, the passivated defects can be reactivated by the protons generated by radiation, which significantly affects the device performance and causes reliability issues. In this review, computational studies on the amorphous SiO2/Si interface and interface defects are summarized, including the modeling of the interface, the main interface defects, and their depassivation, and compared to experimental results. The hyperfine parameters are emphasized, because they are essential to identify the structures of the interface defects. The defect levels and depassivation of the defects are also emphasized, because the former directly affect the device performance and the latter directly generates the dangling bonds in the interface.

Quantum-chemical study of structure and vibrational spectra of Si/SiO-=SUB=-2-=/SUB=- superlattices

“…Structure and properties of the Si/SiO 2 interface were targets of many theoretic studies based on computer simulation using the method of density functional [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”

“…As a rule, in real samples the oxide layer is in an amorphous state. Since there are certain difficulties in simulating the amorphous state for theoretical analysis, the calculations used different polymorphic modifications of crystalline silica, such as christobalite [13][14][16][17][18][19]24,[26][27][28], quartz [17,19,21,25,30], or tridymite [15,17,19,20]. Taking into account that most of the studies used christobalite, we decided to start with a model based on this structure.…”

Significant Anharmonicity of Thermal Transport in Amorphous Silica at High Temperature

“…A widely investigated case for thermal transport is amorphous silica (a-SiO 2 ), with extensive applications in microelectronics. [34][35][36] The temperaturedependent κ of a-SiO 2 has been reported at a wide temperature range (1-1200 K) in various experimental studies, [37][38][39][40] but the underlying mechanisms are complex and not fully understood. Zhu and Ertekin reproduced the plateau of the temperaturedependent κ at about 10 K by considering the coexisting populations' and coherences' conduction mechanisms in a model generalized from the Debye-Peierls and AF theory.…”

Теоретическое исследование структуры и колебательных спектров сверхрешеток Si/SiO-=SUB=-2-=/SUB=-

“…Структура и свойства интерфейса Si/SiO 2 были предметом многих теоретических исследований, основанных на компьютерном моделировании с использованием методов функционала плотности [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Ключевой проблемой такого рода исследований был выбор подходящей структурной модели интерфейсного слоя.…”

“…В реальных образцах оксидный слой как правило находится в аморфном состоянии. Поскольку для теоретического анализа моделирование аморфного состояния вызывает определенные трудности, в расчетах были использованы различные полиморфные модификации кристаллического кремнезема, такие как кристобалит [13][14][16][17][18][19]24,[26][27][28], кварц [17,19,21,25,30] или тридимит [15,17,19,20]. Учитывая, что в большинстве работ использовался кристобалит, мы решили начать с модели, основанной именно на этой структуре.…”