Defect generation in oxides of p-channel MOSFETs in presence of water

Hydrogenous species play a key role in radiation§induced charge buildup in metal oxide semiconductor§field effect transistors (MOSFETs). The amount of§hydrogen present in ambient gases used during device§fabrication can be correlated to the concentration of§radiation-induced interface traps post processing.§The effects of water on defect formation in MOSFETs§before and after radiation exposure have been§studied. Greatly enhanced post-irradiation defect§generation was observed in the gate oxides of§p-channel MOS transistors that were exposed to water.§Low frequency (1/f) noise measurements also showed§enhanced noise power spectral densities in the§p-channel transistors consistent with the enhanced§post-irradiation increase in defect density.§Phosphorus and boron dopant atoms are present in the§field oxides of the n-channel and p-channel§transistors because of source and drain implant§steps. This can lead to enhanced water-induced defect§formation in the gate oxides of p-channel transistors§compared to n-channel transistors before and after§irradiation. These results are significant for the§performance of MOS technologies in non-hermetic§environments.