能量粒子轰击金刚石的计算机模拟

A molecular dynamics study of energetic particle bombardment on diamond

利用Tersoff势和分子动力学方法研究了初始动能为 5 0 0eV的硼粒子注入金刚石的微观行为 .结果表明 :硼注入后产生温度为 5 0 0 0K的热峰 ,其寿命为 0 18ps;同时产生半径为 0 4 5nm局部非晶化区域 ,三重配位原子数占该区域原子数的 7% .薄膜表层原子向内弛豫 ,近表层原子向外弛豫 ,表面层与近表层原子的间距减少了15 % ,表面层表现为压应力 .硼原子以B <110 >分裂间隙的形式存在于金刚石结构中 .

Molecular dynamic simulations, utilizing the Tersoff many-body potential, are used to investigate the microscopic processes of a single boron atom with an energy of 500 eV implanted into the diamond (001) 2 x 1 reconstructed surface. By calculating the variation of the mean coordination number with time, the lifetime of a thermal spike created by B bombardment is about 0.l8ps. Formation of the < 110 > split-interstitial composed of projectile and lattice atom( B-C) is observed. The total potential energy of the system decreases about 0.56 eV with a stable B < 110 > split-interstitial existing in diamond. Lattice relaxations in the diamond (001) 2 x 1 reconstructed surface or near surface of the simulated have been discussed, and the results show that the outermost layer atoms tend to move inward and other atoms move outward, while the interplanar distance between the outermost layer and the second layer has been shortened, by 15% compared with its starting interplanar distance. Stress distribution in the calculated diamond configuration is inhomogeneous. After boron implanted into diamond with an energy of 500 eV, there is an excess of compressively stressed atoms in the lattice, which induces the total stress being compressive.