Method of manufacturing dual gate semiconductor device
The method involves providing a semiconductor substrate comprising first and second regions in which different conductive metal-oxide semiconductor (MOS) transistors are to be formed. A gate dielectric layer above the semiconductor substrate sequentially forming a first metallic conductive layer and a second metallic conductive layer on and above the gate dielectric layer; covering the second region with a mask, and performing ion plantation of a first material into the first metallic conductive layer of the first region. Removing the second metallic conductive layer of the first region and forming a first gate electrode of the first region and a second gate electrode of the second region by patterning the gate dielectric layer and the first metallic conductive layer of the first region, and the gate dielectric layer, the first metallic conductive layer, and the second metallic conductive layer of the second region. The first and second regions of the semiconductor substrate having different work functions because the gate electrodes of the first and second regions have different thicknesses and at least one of the first and second gate electrodes include impurities.
1. A method of manufacturing a dual gate semiconductor device, the method comprising:
providing a semiconductor substrate having first and second regions in which different conductive MOS (metal-oxide semiconductor) transistors are to be formed;
forming a gate dielectric layer over the semiconductor substrate;
sequentially forming a first metallic conductive layer and a second metallic conductive layer over the gate dielectric layer;
covering the second region with a mask;
performing ion plantation of a first material into the first metallic conductive layer over the first region;
removing the second metallic conductive layer over the first region; and
forming a first gate electrode over the first region and a second gate electrode over the second region by patterning the gate dielectric layer and the first metallic conductive layer of the first region, and the gate dielectric layer, the first metallic conductive layer, and the second metallic conductive layer of the second region.
2. The method of claim 1 , wherein the first region is a region in which an NMOS (n-type metal-oxide semiconductor) transistor is formed and the second region is a region in which a PMOS (p-type metal-oxide semiconductor) transistor is formed.
3. The method of claim 1 , wherein the gate dielectric layer comprises a material selected from the group consisting of HfO 2 , HfSiO, HfON, HfSiON, ZrO 2 , ZrON, ZrSiO 2 , ZrSiON, and TiO.
4. The method of claim 1 , wherein the first metallic conductive layer has a thickness between 1 through 5 nm.
5. The method of claim 1 , wherein the second metallic conductive layer has a thickness between 5 through 50 nm.
6. The method of claim 1 , wherein the second metallic conductive layer has a thickness greater than 5 nm.
7. The method of claim 1 , wherein the first metallic conductive layer comprises a material selected from the group consisting of Ti, Ta, W, Hf, Mo, nitrides of these, carbides of these, silicides of these, and silicide nitrides of these.
8. The method of claim 1 , wherein the second metallic conductive layer is formed of a material different from that of the first metallic conductive layer.
9. The method of claim 1 , wherein the second metallic conductive layer comprises a material selected from the group consisting of Pt, Ru, IrO, RuO, metal aluminum, and metal aluminum nitride, as well as Ti, Ta, W, Hf, Mo, nitrides of these, carbides of these, silicides of these, and silicide nitrides of these.
10. The method of claim 1 , wherein the first material comprises As.
11. The method of claim 1 , wherein, before sequentially forming the first metallic conductive layer and the second metallic conductive layer, the method further comprising:
forming a first capping layer on the gate dielectric layer over the first region; and
forming a second capping layer over the gate dielectric layer in the second region.
12. The method of claim 11 , wherein the first capping layer comprises a material selected from the group consisting of LaO, GdO, DyO, ErO, SrO, and BaO.
13. The method of claim 11 , wherein the second capping layer comprises Al or AlO.
14. The method of claim 11 , wherein the second capping layer comprises a material different from that of the first capping layer.