Method for patterning a lanthanum containing layer

A semiconductor device comprising:

• a first transistor having a first active region, the first transistor comprising a first gate structure, the first gate structure comprising:
• a first high-k dielectric layer over a portion of the first active region, the first high-k dielectric layer comprising a first material;
• a first work function layer over the first high-k dielectric layer, the first work function layer comprising a second material;
• and
• a first conductive fill over the first work function layer, the first conductive fill comprising a third material;
• and
• a second transistor having a second active region, the second transistor comprising a second gate structure, the second gate structure comprising:
• a second high-k dielectric layer over a portion of the second active region, the second high-k dielectric layer comprising the first material doped with lanthanum, wherein the second high-k dielectric layer comprises titanium, wherein a concentration of titanium in the second high-k dielectric layer is less than or equal to about 0.1 atomic percent;
• a second work function layer over the second high-k dielectric layer, the second work function layer comprising the second material;
• and
• a second conductive fill over the second work function layer, the second conductive fill comprising the third material.