Hi,

Jpt, about your post on ohmic contact to silicon, is your silicon p-type or
n-type or just plain undoped sillicon?

We are experiencing difficulties with getting ohmic contact to our P-type B ion
implanted silicon cantilevers.
Our surface doping concentration (required for good piezoresistivity) is on the
order of 10^18 according to simulation.

Currently we are using 5000A Au with 500A Ti as interfacial layer for electrical
connection. Gold or copper on the top layer is a requirement for our wire-
bonder.

We performed a quick local oxide removal before the evaporation.
No anealing is performed after metalization, to avoid diffusion of gold.
On the I-V curve, we observe a turn-on voltage of approximately 0.2V.

We could do a double-doping process to have a different concentration for
contact than for the piezoresistors, but what doping level should we shoot for
on the contact regions?

Please correct me if am wrong, but I would suppose that the metal choice for
n-type and p-type silicon would be very different, due to band structure, right?

Any suggestions/references on choice of metal, annealing recipes, and doping
would be greatly appreciated.

Nannan