Dear all,

When I use an west bond 7400A Aluminum ultrasonic wirebonder , before I did the
wirebonding, the resistance between the two metal pads was >10 Mohm, but after I
did the wire bonding, the resistance dropped to a few hundred ohm to a few kohm.
the other ends of the two metal pads are separated by a 150 nm trench of GaAs.
This happened to 3 of my devices, and now I only have one left...

does anyone know what might be the cause of this?

thanks 1000 times!

 mufei