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借助于Tersoff势函数和分子动力学模拟技术研究了室温下500eV的能量粒子硼(4个)和氮(8个)共掺入金刚石晶体中所引起的损伤区域内晶体微细观结构的变化特征以及后续加热退火晶体结构的演变特征.结果表明:随着掺入原子数目的增加,受影响的区域范围渐渐增大,12个粒子全部注入金刚石晶体后局部影响区域的半径达0.68nm,损伤区域中心的三配位原子数增加而四配位数原子数量减少.加热退火过程中损伤中心区域的原子发生扩散,部分原子的扩散距离达到4个晶格间距.加热退火使损伤区域中心原子间的平均键长趋于金刚石结构的键长.退火后薄膜中注入的杂质原子向表面扩散引起应力分布产生变化,杂质原子经过一系列的扩散过程能够到达空位的位置,减少薄膜中空位数量,减小晶格畸变程度,原子向表面扩散引起应力产生重新分布,薄膜中应力峰值的峰位向薄膜表面发生移动,局部应力集中程度降低.通过不同退火温度的比较发现低温下退火(800℃)更有利于空位的运动和晶格损伤的恢复从而提高晶格质量.
With the help of Tersoff potential function and molecular dynamics simulation, the microstructural changes in the damaged region caused by co-incorporation of boron (4 atoms) and nitrogen (8 atoms) into the diamond crystal at 500eV at room temperature were investigated. The results show that with the increase of the number of doped atoms, the affected area increases gradually. The radius of the local influence area after all the 12 particles are implanted into the diamond crystal reaches 0.68 nm, and the center of the damaged area The atomic number of the four coordination number is increased and the number of atoms of the four coordination number is reduced.The atoms in the damaged central region diffuse in the heating annealing process and the diffusion distance of some atoms reaches 4 lattice spacing.The average annealing temperature The bond length tends to the bond length of the diamond structure.After the annealing, the impurity atoms diffused into the surface of the film cause the stress distribution to change, and the impurity atoms can reach the vacancy position through a series of diffusion processes to reduce the number of vacancies in the film, The degree of lattice distortion, the diffusion of atoms to the surface causes stress to redistribute the peak of the stress peak in the film to the film table Moves, reduce localized stress concentration by comparing different annealing temperatures found at a low temperature annealing (800 deg.] C) and is more conducive to the recovery movement of the lattice damage lattice vacancies to improve the quality.