EFFECT OF HYDROGEN ON TRAP GENERATION, POSITIVE CHARGE TRAPPING, AND TIME-DEPENDENT DIELECTRIC BREAKDOWN OF GATE OXIDES.

The effect of high-temperature ( approximately equals 900 degree C) hydrogen on the gate oxides of MOS devices is studied. Hydrogen is introduced into devices by either high-temperature anneal or conventional process steps such as low-pressure chemical vapor deposition (LPCVD) of Si//3N//4. In all cases, measurements of high-field stress behavior show that high-temperature hydrogen steps reduce time to breakdown and increase bulk and interface trap generation, but do not affect the generation of positive charge. These results indicate that the wear-out mechanism of gate oxides at high fields is related to trap generation rather than to accumulation of positive charge.