Several comments:

1) Forget dipping in HF.  The two people suggesting it have stated
they've never done it.  It will screw up your metal (there are pinholes
galore in the native oxide on Ti; HF attacks most metals, and is
particularly well-suited to etch Ti; you'll end up with either Swiss
cheese Ti, or no Ti at all, depending upon stress and thickness).

2) The posters who pointed to Ni, or controlling Au thickness, or
deposited Ti again before final Au dep, have made IMO good suggestions.

3) But, we have had good success with an Ar sputter prior to Au dep.
You might consider that approach.

Al
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Albert K. Henning, PhD
Director of MEMS Technology
NanoInk, Inc.
215 E. Hacienda Avenue
Campbell, CA  95008
408-379-9069  ext 101
[email protected]