锰的硅化物薄膜在Si(111)-7×7表面的固相反应生长

Growth of Manganese Silicide Thin Films on Si(111)-7×7 Surfaces by a Solid Phase Reaction

利用超高真空扫描隧道显微镜(STM)对沉积在Si(111)-7×7重构表面上的锰薄膜在300-650℃之间的固相反应进行了研究.锰原子最初在Si(111)衬底上形成锰的纳米团簇的有序阵列,经过300℃退火后,锰纳米团簇的尺寸增大并且纳米团簇阵列由有序变为无序;当退火温度达到400℃左右时,锰纳米团簇与硅衬底发生反应生成富锰的三维岛状物和由MnSi构成的平板状岛;500℃退火后生成物全部转变为MnSi平板状岛;650℃退火后生成物则由MnSi平板状岛全部转变为富硅的不规则的大三维岛,同时被破坏的衬底表面重新结晶形成7×7结构.

Ultrathin manganese films were deposited onto Si（111）-7×7 surfaces by electron-beam evaporation.The solid phase reaction between the manganese thin film and the Si（111） substrate between 300 and 650 ℃ was studied in situ by ultrahigh vacuum scanning tunneling microscopy（STM）.The deposited Mn atoms form an ordered nanocluster array on the Si（111） surface at room temperature.When the sample was annealed at 300 ℃,the Mn nanoclusters increased in size and the nanocluster array became disordered.When the annealing temperature reached about 400 ℃ the Mn began to react with the Si and the products consisted of three-dimensional（3D） and tabular islands.The tabular islands are a MnSi compound and the 3D islands are Mn-rich silicides.The MnSi tabular islands were the only product when the sample was annealed at 500 ℃.At an annealing temperature of 650 ℃,the MnSi tabular islands converted into large 3D islands which were likely Si-rich manganese silicides and the destroyed substrate surface reverted to the 7×7 structure through recrystallization.