Dear All,
   I am using an ebeam system to deposite metal film
on semiconductor wafer. When I evaporated Au, Ni, Ti,
there were no problems. But now when I use Al, I can
not obtain deposition rate. Though the Al material in
crucible totally melts, the deposition rate, which is
given by the detect crystal above the crucible,is
still zero. Another strange phenomenon is that the
observation window, which is on the cavity wall a
little higher than the crucible, is coated with Al. I
am sure the 5N Al material we are using has no
problem. I think maybe all those evaporated Al atoms
were bombed to form Al ion by e-beam and rotated to
the window by megnetic field. What should I do? Adjust
the magenetic field? Or any other ways?
  Thanks for any help.

ZHU X.P.