ELECTROLESS NICKEL PLATED CONTACTS ON POROUS SILICON

We have presented the electroless nickel plating technique as a prefer red method for making ohmic or rectifying contacts on porous silicon. Nickel, plated by this technique, penetrates the pores and forms conta ct on an effective area, about 4.5 times the actual area of the sample . High-temperature annealing of the plated metal produced excellent oh mic contacts with porous silicon formed on n-type silicon. The propert ies of this contact are shown to be much superior to that of conventio nal evaporated and alloyed ohmic contacts made on p-type porous silico n of identical characteristics. Contacts made under similar conditions by electroless nickel plating on p-type porous silicon, on the other hand, showed good rectifying diode characteristics. The observed elect rical properties of electroless nickel contacts are believed to be due to the presence of minute amounts of phosphorous with the plated meta l. (C) 1996 American Institute of Physics.