Patent ID: 7432164

Claim:
A method of making a semiconductor device, comprising: providing a first substrate region and a second substrate region, wherein at least a part of the first substrate region has a first conductivity type and at least a part of the second substrate region has a second conductivity type different from the first conductivity type; forming a dielectric layer over at least a portion of the first substrate region and at least a portion of the second substrate region; forming a first metal-containing gate layer over at least a portion of the dielectric layer overlying the first substrate region; forming a second metal-containing gate layer over at least a portion of the dielectric layer, over at least a portion of the first metal-containing gate layer, and over at least a portion of the first substrate region; forming an amorphous silicon layer over the second metal-containing gate layer; introducing dopants into at least a portion of the first substrate region through at least the first metal-containing gate layer, the second metal-containing gate layer, and the amorphous silicon layer; and patterning the dielectric layer, the first and second metal-containing gate layers, and the amorphous silicon layer to form a gate stack over the first substrate region.