Reduction of sidewall defect induced leakage currents by the use of nitrided field oxides in silicon selective epitaxial growth isolation for advanced ultralarge scale integration

Defects in the near sidewall region in selective epitaxial growth of silicon have prevented its widespread use as a viable dielectric isolation technology. The main cause of these defects has been demonstrated to be thermal stress due to mismatch in the coefficient of thermal expansion between silicon and silicon dioxide. This article presents the detailed electrical characterization of these sidewall defects using P1/N junction diodes fabricated using silicon dioxide and thermally nitrided silicon dioxide as the field insulator. It is shown that the use of field oxide which was nitrided at 1100 °C for 60 min in ammonia gas ambient reduced the reverse saturation current density in the diodes by a factor of 6 and also improved the forward recombination and ideality factors when compared to standard thermal field oxide isolated diodes. The improvement of the sidewall quality was attributed to a reduction in thermal stress due to the modification of the coefficient of thermal expansion of nitrided silicon oxide. © 2000 American Vacuum Society. @S0734-211X~00!08802-8#