LOW-TEMPERATURE FURNACE-GROWN REOXIDIZED NITRIDED OXIDE GATE DIELECTRICS AS A BARRIER TO BORON PENETRATION

Reoxidized nitrided oxide (ROXNOX) gate dielectrics, known for their resistance to hot-electron effects and their radiation hardness, also can be used to block the diffusion of boron into the MOS channel region. Recent studies have reported on reduced boron diffusion through rapid-thermal-processed reoxidized nitrided oxides. However, these studies have not addressed the possibility that fixed oxide charge annealing can mask the effects of boron in the channel, a particularly important consideration for low-temperature gate oxides. In this work, we separate the effect of fixed charge annealing from the effect of boron diffusion, and unambiguously demonstrate that a low-temperature furnace-grown reoxidized nitrided oxide has a substantial advantage over conventional gate oxides in protecting the channel from boron, over a wide range of annealing times and temperatures. We also address the issue of fixed charge annealing in low-temperature reoxidized nitrided oxides, and present an approach to maintain acceptable gate dielectric quality while preserving a low D . t product for integration into a scaled dual-gate CMOS process.