【摘要】 B和O是太阳能级多晶硅中的主要非金属杂质,它们经常以B-O原子对的形式存在。利用第一性原理计算方法,通过对比B-O对在真空、B2O3和硅中的键合状态,理解Si环境对B-O键合特征的影响。计算结果表明,在这3种原子环境中,O原子的s和p轨道对键合的贡献都比B原子的s和p轨道大得多。其中,在真空中主要是O的2p轨道参与成键,而在氧化物和硅中O原子的2s轨道和2p轨道都参与成键。在硅中,由于B-O间距较大,以及与Si键合导致B-O键合电子态密度的降低,使B-O对在硅中的结合强度低于在氧化物和真空中。更多还原

【Abstract】 Boron and oxygen are the major non-metallic impurities in solar-grade polysilicon,and they often exist in the form of B-O pair.To understand the effect of silicon environment on B-O binding state,the binding states of B-O pair in vacuum,oxide,and silicon were compared by the first-principle calculations.The results show that the contribution of s and p orbitals of oxygen to the bonding state is always higher than that of the boron.However,in B2O3 and silicon,2s and 2p orbitals of oxygen are mainly involved in bonding,while in vacuum,2p orbital of oxygen contributes more.In silicon,because the B-O spacing is relatively large,and the B-O electronic density of states for the bonding is decreased by the bonding with the silicon,the bonding strength of B-O pair in silicon is lower than those in B2O3 and vacuum.更多还原