Thermal and stress studies of the 30.4 nm Mo/Si multilayer mirror for the moon-based EUV camera

To investigate the environmental adaptability of the Mo/Si multilayers on lunar surface, we studied the stability and stress of Mo/Si multilayers under the low and high temperature environment. The in-situ X-ray diffraction (XRD) and the ex-situ intrinsic stress are measured in the temperature range from - 135 degrees C to 600 degrees C and from 190 degrees C to 600 degrees C, respectively. The results demonstrate that the periodic structure of Mo/Si multilayers is stable between 135 degrees C and 300 degrees C. The stress is unaffected under low temperature and it gradually increases from 260 MPa to 1G MPa when the temperature changes from room temperature to 600 degrees C. Above 600 degrees C, large tensile stress leads to folds and cracks in the film. Thus, the large temperature range on lunar surface has little effect on the structure, performance and stress of the Mo/Si multilayers and the high temperature in lunar day releases the stress of the multilayer mirror. (C) 2014 Elsevier B.V. All rights reserved.