Atomistic mechanism of the initial oxidation of the clean Si(100)-(2×1) surface by O2 and SiO2 decomposition
Atomistic mechanism of the initial oxidation of the clean Si(100)-(2×1) surface by O2 and SiO2 decomposition
复制标题
O2 和 SiO2 分解对清洁 Si(100)-(2×1) 表面进行初始氧化的原子机制
DOI：
10.1063/1.1456036
复制
发表时间：
2002
影响因子：
4.4
通讯作者：
C. Musgrave
中科院分区：
文献类型：
--
作者：
Y. Widjaja;C. Musgrave
采用密度泛函理论模拟研究了分子氧氧化裸Si(100)-（2×1）表面的反应机理。O2分子吸附在“上”面Si原子上，无激活垒，吸附能为35 kcal/mol。发现被吸附的O2带负电荷。O2(a)转化为过氧化氢桥结构，势垒为10千卡/摩尔，放热为33千卡/摩尔。桥接的过氧化物O2通过首先将一个氧原子插入Si-Si二聚体键中，然后将剩余的氧原子插入Si-Si背键来解离。第一次和第二次氧插入的激活势垒分别为36 kcal/mol和13 kcal/mol。我们还计算了SiO2薄膜分解的激活屏障，这种分解在高温下变得普遍，其中SiO(g)从SiO2薄膜中解吸。SiO的解吸势垒在65 ~ 67 kcal/mol之间。
Density functional theory simulations are used to investigate the reaction mechanism of oxidation of the bare Si(100)-(2×1) surface by molecular oxygen. O2 adsorbs molecularly on the “up” surface Si atom with no activation barrier and an adsorption energy of 35 kcal/mol. Adsorbed O2 is found to be negatively charged. O2(a) then transforms into the peroxide bridge structure with a barrier of 10 kcal/mol and exothermicity of 33 kcal/mol. The bridged peroxide O2 then dissociates by first inserting one oxygen atom into the Si–Si dimer bond followed by insertion of the remaining oxygen atom into a Si–Si backbond. The activation barriers are 36 kcal/mol and 13 kcal/mol for the first and second oxygen insertions, respectively. We have also calculated the activation barriers for SiO2 film decomposition, which becomes prevalent at high temperatures, in which SiO(g) desorbs from SiO2 films. The SiO desorption barriers are found to be in the range of 65–67 kcal/mol.