AMMONIA NITRIDATION OF THERMAL POLYOXIDE TO ELIMINATE EPITAXIAL AMBIENT INDUCED DIELECTRIC PINHOLE FORMATION

The incorporation and distribution of nitrogen in ammonia nitrided the rmal polyoxide (NPOX) dielectric films and their degradation durabilit y to reduced pressure, dichlorosilane (SiH2Cl2)-HCl-H-2 ambient during epitaxial lateral overgrowth (ELO) indicated that the surface nitroge n concentration had no effect. However, a bulk nitrogen concentration as low as 8 at. % significantly reduced the formation of ELO ambient i nduced pinholes in 250 Angstrom polyoxide films. After 40 min of ELO a mbient stress the electrical yield was raised from 0%, for the control polyoxide dielectric capacitors, to 84% for NPOX dielectric capacitor s. Analyses of the failed devices suggest that active pinhole generati on still exists, however, the bulk nitrogen concentration dramatically reduces the frequency and rate at which these dielectric defects are produced. (C) 1996 American Vacuum Society.