COPPER ADSORPTION BEHAVIOR ON SILICON SUBSTRATES

Copper contamination behavior is studied, depending on the pH level, c onductivity type P or N of a silicon substrate, and contamination meth od of copper. If the pH level of a copper containing solution is adjus ted by using ammonia, copper atoms and ammonia molecules produce coppe r ion complexes. Accordingly, the amount of copper adsorption on the s ubstrate surface is decreased. When N-type silicon substrates are cont aminated by means of copper containing solutions, copper atoms on the surfaces diffuse into bulk crystal even at room temperature. But for P -type silicon substrates, copper atoms are transferred into bulk cryst al only after high temperature annealing. In the case of silicon subst rates contaminated by contact with metallic copper, no copper atom dif fusion into bulk crystal was observed. The above mentioned copper cont amination behavior can be explained by the charge transfer interaction of copper atoms with silicon substrates.