Hello all,

  I need to make ohmic contacts to p-type silicon resistors. I am using aluminum
 for this purpose but all the contacts that I have had so far have been showing
 a diode behavior. I have evaporated aluminum at a pressure of about 10^-6 Torr
 using a Tungsten boat, and then sintered the sample in oven (450C for 45min).

  All the contacts show a forward bias voltage of around 2.5V and a reverse
 breakdown voltage of around -8V. These numbers are not even close to Schotky
 diode values. I did not expect formation of diodes, since aluminum itself is
 a p-type dopant of silicon, and I should have a p+-p type of junction.

  Does anybody know how to solve this problem? Any comments will be highly
 appreciated.

  Thank you in advance.

  Regards,
  Behraad Bahreyni

_____________________________________________________________________

  Behraad Bahreyni
  Material Research Laboratory, Department of ECE
  The University of Manitoba
  15 Gillson Street, Winnipeg, Manitoba, Canada   R3T 5V6

  Tel:   +1-(204)-951 2027       Fax:   +1-(204)-261 4639
  email: Behraad@ieee.org        http://www.ee.umanitoba.ca/~bahreyni