T Hreshold V Oltage C Ontrol S Chemes in F Infets

Conventionally polysilicon is used in MOSFETs for gate material. Doping of polysilicon and thus changing the workfunction is carried out to change the threshold voltage. Additionally polysilicon is not favourable as gate material for smaller dimensional devices because of its high thermal budget process and degradation due to the depletion of the doped polysilicon, thus metal gate is preferred over polysilicon. Control of workfunction in metal gate is a challenging task. The use of metal alloys as gate materials for variable gate workfunction has been already reported in literature. In this work various threshold voltage techniques has been analyzed and a novel aligned dual metal gate technique is proposed for threshold voltage control in FinFETs.