Thermal Strain of In films deposited onto Si and GaAs Substrates

沉积在 Si 和 GaAs 衬底上的 In 薄膜的热应变

基本信息

批准号：
03452257
负责人：
MURAKAMI Masanori
金额：
$ 4.67万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452257/
关键词：
thin film thermal strain In In X線回析

项目摘要

An investigation has been carried out of the thermal strain in In films deposited onto Si and GaAs substrates at 300k and 77k and then cooled down to temperatures as low as 20k. The strain in the In caused by differences in thermal expansion of In, and Si and GaAs was measured using X-ray diffraction techniques. Also the magnitude of the strain at 20k was found to approximate the strain value calculated from the difference in the thermal expansion coefficients using the biaxial strain model. For the In films, the crystallographic anisotropy both of the thermal expansion coefficient and Young's modulus was considered in calculations. The surface morphologies of In films evaporated in a vacuum of 10^<-7>-^<-6>were changed from island to continuous structures. The continuous films were obtained after that pre-evaporation of In was carried out in a vacuum chamber. Therefore, the change of film morphologies appeared to be caused by the oxygen concentration in the vacuum chamber. The thicknesses if In films were 100 to 140 nm. Since the thermal expansion coefficient of In film was greater than that of Si and GaAs substrates, compressive strain in the vertical direction of film was occurred according as the temperature was down room temperature to 20k. The measured and calculated strain values have a strong dependence on the crystal orientations. A large strain of -1.0%was obtained for (001) oriented grain and small strains of -0.6%were (111), (001) and (313) oriented grains. The dependence on the grain orientation of measured strain values was well agree with calculated strain values. Although the measured strain value were increased as the thickness of films decreased and films were more continuous, the measured strain values merely reached to -70%of the strain values expected by calculation. This mean that the film occurred the relaxation by plastic deformations.

在沉积在300k和77k上的膜中的热应变中，已经进行了调查，然后冷却至20K的温度。使用X射线衍射技术测量IN和Si和GaA的热膨胀引起的IN应变。同样，发现使用双轴应变模型从热膨胀系数的差异计算出的应变值也近似于近似于20K处的应变值。对于在膜中，在计算中考虑了晶体学各向异性的热膨胀系数和Young的模量。在10^<-7> - ^<-6>真空中蒸发的膜中的表面形态被从岛上变为连续结构。在真空室内进行预先蒸发后，获得了连续的膜。因此，膜形态的变化似乎是由真空腔中的氧气浓度引起的。如果胶片中的厚度为100至140 nm。由于膜中的热膨胀系数大于SI和GAAS底物的热膨胀系数，因此由于温度下降至20K，因此在膜的垂直方向上发生了压缩应变。测得的和计算出的应变值对晶体方向具有很强的依赖性。（001）面向的谷物和-0.6％的小菌株获得了-1.0％的大量应变，为（111），（001）和（313）面向晶粒。对测量应变值的晶粒方向的依赖性与计算出的应变值非常一致。尽管随着膜的厚度减小和膜更连续的厚度，测得的应变值增加了，但测得的应变值仅达到通过计算预期的应变值的-70％。这意味着胶片是通过塑性变形出现的。