Maximum Allowable Surface Research Articles

Der einfluss adsorbierter metallischer verunreinigungen auf die kennwerte und die ausfallrate von siliziumgleichrichteranordnungen

A study is made on simple alloyed silicon rectifiers with copper impurities in well defined concentrations concerning the effects of adsorbed copper from different solutions on reverse current, characteristics and reliability. It is shown that for the surface concentration there exists a threshold, by exceeding of which a directly damaging influence of the adsorbed copper will become apparent. Based upon this fact for several solutions, characteristic for different adsorption mechanism, the maximum allowable surface concentrations and the corresponding maximum allowable copper ion concentrations in the solutions are presented. The great differences in the allowable copper ion concentrations suggest a revision and differentiation of the purity standards for the etching and cleaning agents used in semiconductor technology.