Mobility behaviour of n-channel and p-channel MOSFETs with oxynitride gate dielectrics formed by low-pressure rapid thermal chemical vapor deposition

The electric field dependence of electron and hole mobility was investigated in n-channel and p-channel metal-oxide-semiconductor field-effect transistors with oxynitride gate dielectrics formed using low-pressure rapid thermal chemical vapor deposition with SiH/sub 4/, N/sub 2/O and NH/sub 3/ as the reactive gases. The peak electron mobility was observed to decrease with increasing nitrogen and hydrogen concentration whereas the high-field mobility degradation was improved. The hole mobility was observed to decrease for all electric fields. A self-consistent physical explanation for the observed electron and hole mobility behaviour is suggested based on the electrical results. We attribute the observed mobility characteristics mainly to the trapping behaviour of these films.