Dopant penetration effects on polysilicon gate HfO/sub 2/ MOSFET's

Effect of dopant penetration on electrical characteristics of polysilicon gate HfO/sub 2/ gate dielectric MOSFETs has been studied quantitatively for the first time. Significant boron penetration was observed at high temperature dopant activation, which degrades not only flatband voltage (V/sub fb/) but channel carrier mobility. Surface nitridation prior to HfO/sub 2/ deposition can suppress boron penetration along with equivalent oxide thickness (EOT) reduction.