Just After Cl-ICP

After HF etch, and 250’C 2.5h anneal

In some area, the Ni was totally removed Less membrane supporting, some lines wrap and break

Two remaining problems:1. The Ni/SiO2/HfO2 from the backside is not so easy to be fully removed,

and I could not get reproducible good TEM images.2. The Ni lines on top of the Ni are attached by the Cl-ICP etch.

Possible Solutions:

1. Dry the Ni-InGaAs bonding again with the small-window TEM grid, as well as thinner Ni layer that will not react all through the 50nm InGaAs.

2. Writing the fins with HSQ fully cover the Ni to protect it, and use thicker Ni (200 nm).