Degradation of N/sub 2/O-annealed MOSFET characteristics in response to dynamic oxide stressing

The performance of n-MOSFETs with furnace N/sub 2/O-annealed gate oxides under dynamic Fowler-Nordheim bipolar stress was studied and compared with that of conventional oxide (OX). Time-dependent dielectric breakdown at high frequency was shown to be improved for the N/sub 2/O-annealed devices compared with that for devices with OX. In addition, a smaller V/sub t/ shift after stress was found for nitrided samples. The shift decreased with increasing stressing frequency and annealing temperature. Measurements of both G/sub m/ and D/sub it/ revealed a peak frequency at which the degradation was the worst. A hole trapping/migration model has been proposed to explain this.<
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