Hi,
I am trying wet etch gold film from 60nm down to 30nm.  My lab has 2 available
chemistries, KCN and KI:I2 chemistries.  Due to the potential toxicity of KCN, I
have chosen to use the KI/I2 chemistry in the proportion KI:I2:H2O = 4:1:40ml.
I have tested this chemistry on 80nm of gold evaporated on PDMS.  In the
literature it was reported that KI/I2 chemistry in the proportion I used can
etch gold at a rate of 1 micron per min, but in my trial, I have discovered that
the 80nm gold film takes 6 times longer to remove.  The removal of the gold is
not complete as there is still a thin layer of gold film left behind.
Can anyone suggest a more effective and controllable way to wet etch gold?

Mr. Jeffrey Mun Pun YUE
???
Division of Bioengineering
Block E3, #05-18, Nanobioanalytics Lab
9 Engineering Drive 1
National University of Singapore
Singapore 117576
Tel: (65) 65165985, Fax: (65) 68723069
E-mail:  g0500396@nus.edu.sg