掺杂Ti的纳米CrSi2薄膜的制备

摘要

Ti doped CrSi2 films doping Ti were synthesized by depositing alternatively Cr,Ti and Si layers using multi-target magnetron sputtering system and following annealing in vacuum.The survival deposited Si phase and a few synthetic CrSi phase as well as the (Cr,Ti)Si2 phase exist in films when the deposited alternatively films were annealed for 2 h at 500 ℃.The deposited Si phase and CrSi phase reduced but (Cr,Ti)Si2 phase in-creased with extending annealing time.The mean grain size computed according to half height wide of X-ray dif-fraction peak by Debye-Scherrer equation showed that the grain size of (Cr,Ti)Si2 phase increased approximate-ly linearly from 68 to 81 nm as the annealing time increases from 2 to 8 h.The films obtained by annealing were nanostructured with (111)orientation.The diffraction angle of (Cr,Ti)Si2 phase (111)plane gradually moved to small value with increasing Ti atom fraction,which suggested that the crystalline constant a and c of (Cr,Ti) Si2 phase increase gradually.The variation of crystalline constant showed approximately linear relation with Ti atom fraction due to the substitution of Cr atom by the Ti atom with longer radius in lattice.The computation and analysis showed that the epitaxial growth of (Cr,Ti)Si2(111)on Si(100)results from the low lattice distor-tion energy at interface.The level of CrSi2(111)prefer orientation decreased with increasing Ti atom fraction.%利用多靶磁控溅射设备交替沉积 Cr、Ti 和Si层,并通过随后的真空退火处理,制备了掺杂 Ti 的CrSi2薄膜.交替沉积薄膜500℃退火2 h,薄膜中除含有(Cr,Ti)Si2相外,还有部分残留的沉积 Si 相和少量反应生成的 CrSi 相；退火时间增加,沉积 Si 相和CrSi相减少而(Cr,Ti)Si2相增多；500℃退火6 h及以上时,薄膜中仅有(Cr,Ti)Si2相.测量薄膜 X 射线衍射峰半高宽,利用谢乐公式估算薄膜平均晶粒尺寸表明,退火时间从2 h增加到8 h,薄膜中(Cr,Ti)Si2相晶粒尺寸由68 nm近似线性增加到81 nm.退火获得的(Cr,Ti)Si2薄膜具有纳米结构和(111)面单一取向.随着掺杂Ti 原子分数的增加,薄膜 X 射线衍射谱中(Cr,Ti)Si2(111)晶面衍射角逐渐向低角度方向移动,这反映(Cr,Ti)Si2相的晶格常数a 和c 逐渐增大.晶格常数的变化与掺杂Ti的原子分数近似呈线性关系,这是结构中半径较大的Ti原子替换半径较小的 Cr原子所造成的.计算分析显示,单晶 Si(100)上(Cr,Ti) Si2(111)晶面外延生长是它们的界面晶格畸变能较低的结果；Ti 原子分数增加,(Cr,Ti)Si2薄膜的(111)晶面择优取向程度下降.