Semiconductor device having multi-work function gate electrode and multi-segment gate dielectric

A MOSFET comprising:

• a source and a drain formed in a layer of semiconductor material;
• and
• a gate disposed above the layer of semiconductor material to define a channel interposed between the source and the drain, the gate including:
• a center gate electrode portion having a first work function and being spaced from the layer of semiconductor material by a center gate dielectric, the center gate dielectric establishing a first capacitance from the center gate electrode portion to the layer of semiconductor material;
• and
• a lateral gate electrode portion adjacent each sidewall of the center gate electrode portion and each lateral gate electrode portion having a second work function different from the first work function, and each lateral gate electrode portion being spaced from the layer of semiconductor material by a lateral gate dielectric portion, each lateral gate dielectric portion establishing a second capacitance from the lateral gate electrode portions to the layer of semiconductor material, the second capacitance different from the first capacitance, and the first work function, the second work function, the first capacitance and the second capacitance cooperate so that an absolute value of a device threshold in a center region of the channel is lower than an absolute value of a device threshold in regions of the channel adjacent each of the source and the drain;
• wherein the center gate electrode portion is made from doped polysilicon and the lateral gate electrode portions are made from a metal or metal containing compound.