>>
>> Gold will stick well to silicon if there is no oxide present.  An HF dip
>> immediately preceeding the metallization is usually sufficient, although a
>> pre-dep sputter etch is a good idea if you can sputter the metal (depends
>> on device surface state constraints).  To get good adhesion on nitride, I
>> would recommend a thin chrome or titanium adhesion layer.  Titanium is nice
>> because it's biologically inert and etches easily in very dilute HF
>>
>>
>>
>>
>I don't believe titanium to be an appropriate choice of adhesion
>layer for gold deposition. We have tried and it didn't work for
>us. Even a simple gold wire doesn't stick to a surface with
>titanium on it. I am not sure if there are any especial
>circumstances where gold sticks well to titanium.
>
>--
>Bahram Ghodsian
>
>School of Engineering Science               voice: 604-294 1985
>Simon Fraser University                       fax: 604-291 4951
>Burnaby, BC, V5A 1S6, Canada                 ghodsian@cs.sfu.ca
>
>
I use gold on titanium routinely on both glass and silicon substrates with
excellent results.  Perhaps you are seeing a difference in method of
deposition.  The metals must be vacumn deposited in-situ, or you may form
an oxide on the Titanium, which would degrade adhesion of the gold.