束流密度对Ge/Si量子点溅射生长的影响

摘要

A series of self-assembled Ge quantum dots （QDs） were grown on Si substrate by ion beam sputtering deposition technology. The effects of current density on the size and shape distribution of Ge/Si dots were stud- ied. The measurement of atomic force microscope （AFM） showed that the dot density enhanced with current density increased. Meanwhile, the dome dots were transformed to transitional domes with the dot size de- creased. The uniformity of size distribution became better at the current density of 0.86mA/cm2 compared with the standard deviation of dot diameter. The current density was proportional to the deposition rate of Ge, and it determined the ability to form nucleus from the encounter of ad-atom and other atoms.%采用离子束溅射技术在Si基底上自组织生长了一系列Ge量子点样品,研究了束流密度对Ge/Si量子点的尺寸分布和形貌演变的影响。原子力显微镜测试结果表明,随着束流密度的增加,量子点的面密度持续增大,其尺寸不断减小,量子点的形貌由圆顶形转变为过渡圆顶形。计算直径标准偏差的结果表明,当束流密度为0.86mA/cm2时,量子点的尺寸均匀性最佳。束流密度与沉积速率成正比,影响着表面吸附原子与其它原子相遇而形成晶核的能力。