Oxide breakdown dependence on thickness and hole current - enhanced reliability of ultra thin oxides

Abstract

The link between hole generation/trapping and oxide breakdown is demonstrated by correlating oxide breakdown with the hole current generated in the oxide. Both exhibit the same oxide thickness and field dependences. Charge-to-breakdown (Q <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> ), time-to-breakdown (t <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> ), and breakdown-field (E <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</inf> ) increase dramatically as oxide thickness is reduced below 80 Å due to reduced rate of hole generation, which is modeled by an average electron energy analysis. Time-dependent-dielectric-breakdown (TDDB) tests show that, for as-grown oxide capacitors, defect densities may decrease with decreasing oxide thickness down to 60 Å.