Polysilicon gate with depletion-or-metallic gate with buried channel: what evil worse ?

Metallic gates are expected to overcome polysilicon´s limitations, such as polydepletion. Nevertheless, this option must be associated with buried channel to ensure low V/sub TH/ operation. Taking into account realistic projections on technological capabilities, such as active gate doping, oxide thickness or junction depth, we confirm that the degradation in performances due to the buried channel is definitively much more restrictive than that relative to the polydepletion.