IMPACT OF NITROGEN IMPLANTATION ON HIGHLY RELIABLE SUB-QUARTER-MICRONMETAL-OXIDE FIELD-EFFECT TRANSISTORS (MOSFETS) WITH LIGHTLY DOPED DRAIN STRUCTURE

We studied the effects of nitrogen implantation in the SiO2 sidewall s pacer in detail in order to improve in the reliability of lightly dope d drain (LDD) metal oxide field-effect transistors (MOSFETs), since th e hot carrier degradation of LDD MOSFETs remains one of major issues e ven in the sub-quarter-micron region. It was found that nitrogen impla ntation in the SiO2 sidewall spacer can effectively suppress the hot c arrier degradation of the LDD structure because the nitrogen atoms are segregated at the interface between the sidewall SiO2 and the Si subs trate. This segregation can reduce the generation of interface states or electron traps in the sidewall spacer without causing gate depletio n or an increase in gate resistance. Highly reliable sub-quarter-micro n LDD N-MOSFETs can be realized using this nitrogen implantation techn ique.