采用InGaP和InAlP作为虚衬底的张应变Ge薄膜的材料性质比较

Property Comparison of Tensile-strained Ge Films on Metamorphic InGaP and InAlP Templates

我们利用气态源分子束外延设备在不同In组分的InGaP或InAlP虚衬底上生长Ge薄膜,并比较不同虚衬底上Ge薄膜的材料性质。利用拉曼光谱方法测得生长在InGaP虚衬底上的Ge薄膜最大的张应变量可达1.8%,而生长在InAlP虚衬底上的最大张应变量可达2.0%。通过对表面Ge进行腐蚀并测试电阻的方法,我们发现Ge生长在InGaP上存在平行导电问题,而Ge生长在InAlP上则可以消除平行导电的影响。通过霍尔测试验证了Ge受到张应变时对电子迁移率的提高作用。

We investigated the growth of tensile-strained germanium films grown on metamorphic InGaP and InAlP layers by gas source molecular beam epitaxy,and then compared their properties.For the Ge films grown on the InGaP layers,tensile-strained rate measured by Raman spectra reaches 1.8%,while those on the InAlP the maximum strain rate is up to 2.0%.Parallel conducting channels have been observed in the samples on InGaP template by etching the sample to different depth.However,by using InAlP template the effect of multiple conducting channels is greatly suppressed.We verify that the electron mobility of the Ge film increases with its tensile strain.