【摘要】 研究了单束双能高剂量Ge离子注入、不经过退火在非晶态SiO2薄膜中直接形成镶嵌结构Ge纳米晶的物理机制.实验中利用不加磁分析器的离子注入机,采用Ge弧光放电离化自动形成的Ge+和Ge2+双电荷离子并存的单束双能离子注入方法,制备了1016~1018cm-2多种剂量Ge离子注入的Si基SiO2薄膜样品.用GIXRD表征了Ge纳米晶的存在,并仔细分析得到了纳米晶形成的阈值剂量.通过TEM分析了Ge纳米晶的深度分布和晶粒尺寸.用SRIM程序分别计算了双能离子在SiO2非晶层的射程和深度分布,与实验结合,得到纳米晶形成的物理机制,即纳米晶的形成与单束双能离子注入时Ge+和Ge2+相互碰撞产生的能量沉积在SiO2中形成的局域高温有关.更多还原

【Abstract】 The formation mechanism of Ge nanocrystals （nc-Ge） embedded in a SiO₂ amorphous film is studied.The samples are prepared by Ge ion implantation of mono-beam with two kinds of energy （or charge）,different doses from 1×10 16 to 1×10 18 cm -2 and without subsequent annealing.The solid Ge is ionized to Ge + and Ge 2+ ions under arc discharge.Both Ge + and Ge 2+ ions are accelerated at the voltage of 40kV,without any magnetism analyzer,and implanted into an amorphous SiO₂ film at the same time.The nc-Ge existence is characterized and the threshold dose of the nc-Ge formation is studied by GIXRD.The size and distribution of the nc-Ge are observed by TEM.The Ge ion range and depth distribution in the amorphous SiO₂ film are calculated by an SRIM program.Combining experiment results with theoretical calculation,the physical mechanism of a nc-Ge formation is also obtained,i.e.,it is related to the local high temperature induced by the energy deposition resulting from the collision of Ge + and Ge 2+ during ion implantation.更多还原