Noise Analysis of MOSFET's with Ultra Thin Silicon Oxinitride Films Prepared by Low Pressure Rapid Thermal Chemical Vapor Deposition (LPRTCVD)

The slow oxide trap density of thin RTCVD oxinitride films has been characterized by low frequency noise measurements in MOS transistors. The comparison to the results obtained on thermal oxides clearly demonstrates that the slow oxide trap density is proportional to the excess interface charge and is exponentially dependent on the nitrogen concentration in the film. Moreover, a higher Coulomb scattering rate due to the nitridation induced interface charge explains reasonably well the degradation of the mobility after nitridation.