AFM studies of hydrogen implanted silicon

Abstract

The effects of hydrogen implantation on the surface microtopography of 〈100〉 silicon single crystals were analyzed by means of atomic force microscopy (AFM) technique. The main objective of the study was to get a new insight into the processes occurring during the early stages of hydrogen blister formation in SmartCut® technology used in Silicon-on-Insulator devices manufacturing. The results revealed that hydrogen blistering sets in at doses about 4×10 16 H 2 +/cm 2 by a formation of small, few tens of nanometer high bubbles. The increase of the implantation dose results first in the growth of the bubbles up to few hundreds nm and then in the formation of the next generation of small hydrogen clusters. The detailed analysis of the SiO 2 surface layer formed on the silicon crystals indicated the presence of small, few nm in size, hillock-like structures which can be responsible for the difficulties in SiO 2–SiO 2 face-to-face bonding. A possible use of implantation induced microtopography changes in Microelectronics and Micromechanical Systems applications is also discussed.