Strain and Compositional Analysis of (Si)Ge Fin Structures Using High Resolution X-Ray Diffraction.

The performance of heterogeneous 3D transistor structures critically depends on the composition and strain state of the buffer, channel, and source/drain regions. In this paper we discuss the value of in-line high resolution X-ray diffraction (HRXRD) measurements based on three representative examples. First, we analyzed the strain state of etched Ge fins in the two in-plane directions. We could verify a loss in channel strain after growth of a Si cap which we attribute to Ge reflow. Secondly, we studied the composition and strain state of relaxed SiGe fins selectively grown in an STI matrix where we found an anisotropic in-plane strain state with significantly reduced relaxation in the direction along the fin. Finally, we used HRXRD for the analysis of complex multilayer fin structures which are relevant for horizontal nanowire FETs that are candidates to replace FinFETs below the 7 nm technology node. With this example we could demonstrate that HRXRD is capable of providing insight into fin stress created by interlayer dielectrics (ILD0). [ABSTRACT FROM AUTHOR]