Mechanism for the n-field device failure in double level metal CMOS device

A new mechanism for the n-field device failure in double level metal CMOS integrated circuits using SOG (spin-on glass) films for intermetal oxide planarization is suggested. From the analysis of I-V curve for field devices, junction leakage current and C-V curves of the field oxide capacitor, it is deduced that the degradation in the n-channel isolation characteristics between n/sup +/ and n/sup +/ areas is closely related to the formation of a minority carrier generation center in the p-type silicon substrate, which can provide minority carriers of short generation life time, i.e. donors, rather than by positive charge formation in the field oxide.<>