溅射功率和退火温度对GeSbTe相变薄膜内应力的影响

Influence of sputtering power and annealing temperature on internal stress of GeSbTe phase-change films

通过磁控溅射方法制备了GeSbTe薄膜.借助原子力显微镜,X射线衍射仪和应力测试仪等仪器,并结合对薄膜表面形貌和晶体结构的分析,研究了溅射功率和退火温度对薄膜内应力的影响.结果表明:当溅射功率较小时,内应力随着溅射功率的增大而增大,在50W左右时达到最大值,随后又随着溅射功率的增大而减小.退火温度为160℃时,薄膜发生非晶态向fcc晶态结构的相变,由于Te原子析出到晶粒边界,导致薄膜的内应力急剧增大到最大值为100MPa左右,而后随着退火温度的升高而下降,fcc结构向hex结构转变时,内应力变化并不明显.

GeSbTe films were prepared by RF magnetron sputtering.Based on the analysis about surface topography and crystal structure of the films,the effect of sputtering power and annealing temperature on internal stress was investigated by atomic force microscopy,X-ray diffraction and stress analyzer.Results show that,the internal stress increases with the sputtering power at certain power range,until reaches a maximum stress with the power of 50W,and then decreases with the increasing of sputtering power.Because the Te atoms segregation to the grain boundaries of GeSbTe,an abrupt tensile stress change takes place at the phase transformation from amorphous state to crystalline（fcc） state under thermal anneal treatments at 160℃,the stress reaches a maximum of 100 MPa and then releases to its original value.But there is very little stress change observed at the fcc to hcp transition.