Presentation Information
[16p-PA4-7]Suppression of crack generation and propagation on thick Ge-on-Si (111) by mesa patterning
〇(P)Mohammad Mahfuz Alam1, Yuka Shibahara1, Michihiro Yamada1, Kohei Hamaya2,3,4, Kentarou Sawano1 (1.Advanced Research Laboratories, Tokyo City University, 2.The Univ. of Osaka. Grad. Sch. Eng. Sci., 3.CSRN, The Univ. of Osaka, 4.OTRI, The Univ. of Osaka)
Keywords:
Crack suppression,Crack generation,Crack propagation
Germanium-on-silicon (Ge-on-Si) technology has attracted attention and played a crucial role in fabricating strained SiGe or Ge layers on a Si platform by replacing expensive Ge wafers with more affordable Si wafers for various high-performance SiGe or Ge-based device applications. We investigate crack formation and propagation on thick Ge-on-Si (111) substrates and their suppression by patterning the substrate. Ge-on-Si (111) was fabricated on a patterned Si(111) substrate using a two-step growth method with a solid-source molecular beam epitaxy (MBE) system. Line-shaped cracks were generated on the 3.2 µm thick Ge-on-Si(111) layer outside of the mesa-patterned area and stopped at the edge of the mesa pattern for the etched depth of 3.5 µm, whereas the line-shaped cracks appeared both inside and outside the mesa-patterned area for the etched depth of 1.1 µm. In contrast, the patterned area was completely free from such extra cracks both before and after the ultrasonic treatment. Therefore, the etched depth of the mesa pattern must be greater than the Ge-on-Si layer thickness to obtain a crack-free thick Ge-on-Si(111). Based on this study, the crack-suppression mesa patterning method can be applied to fabricate a thick Ge layer on a Si(111) platform, opening up possibilities for high-performance Ge(111) and SiGe(111)-based devices.