FinFET semiconductor device having increased gate height control
View Patent ↗A semiconductor device includes a silicon-on-insulator (SOI) substrate having a buried oxide (BOX) layer, and a plurality of semiconductor fins formed on the BOX layer. The plurality of semiconductor fins include at least one pair of fins defining a BOX region therebetween. Gate lines are formed on the SOI substrate and extend across the plurality of semiconductor fins. Each gate line initially includes a dummy gate and a hardmask. A high dielectric (high-k) layer is formed on the hardmask and the BOX regions. At least one spacer is formed on each gate line such that the high-k layer is disposed between the spacer and the hardmask. A replacement gate process replaces the hardmask and the dummy gate with a metal gate. The high-k layer is ultimately removed from the gate line, while the high-k layer remains on the BOX region.
1. A semiconductor device, comprising:
a silicon-on-insulator (SOI) substrate including a buried oxide (BOX) layer;
a plurality of semiconductor fins formed on the BOX layer, the plurality of semiconductor fins including at least one pair of fins defining a BOX region of the BOX layer therebetween;
a plurality of gate lines formed on the SOI substrate and extending across the plurality of semiconductor fins, each gate line including at least one metal gate stack;
at least one spacer formed on each metal gate stack; and
a protective layer formed on the BOX region.
2. The semiconductor device of claim 1 , wherein the protective layer comprises a high dielectric (high-k) material.
3. The semiconductor device of claim 2 , wherein the high dielectric material comprises HfO 2 .
4. The semiconductor device of claim 3 , wherein the BOX region comprises SiO 2 , the semiconductor fins are from Si, and the at least one metal gate stack includes a metal gate.
5. The semiconductor device of claim 2 , wherein the protective layer is located between pairs of semiconductor fins among the plurality of semiconductor fins.
6. The semiconductor device of claim 5 , wherein the semiconductor device further comprises a first doped region, a second doped region, and an overlap region where the first region and the second region overlap with respect to one another.
7. The semiconductor device of claim 6 , wherein the first region is an N-region doped with N-type dopants, and the second region is a P-region doped with P-type dopants.
8. The semiconductor device of claim 6 , wherein the overlap region is smaller than the first doped region.
9. The semiconductor device of claim 6 , wherein the first doped region includes a semiconductor fin formed therein among the plurality of semiconductor fins, and wherein the overlap region excludes any semiconductor fins.
10. The semiconductor device of claim 9 , wherein the metal gate stack includes a metal gate.
11. The semiconductor device of claim 6 , wherein the at least one metal gate stack includes a first metal gate stack having a first metal gate in the first doped region and a second metal gate stack having a second metal gate in the overlap region.
12. The semiconductor device of claim 11 , wherein a first height of the first metal gate and a second height of the second metal gate are uniform with respect to one another.
13. The semiconductor device of claim 12 , wherein the first metal gate and the second metal gate do not extend laterally over the at least one spacer.
14. The semiconductor device of claim 13 , wherein the at least one spacer comprises:
a first pair of gate spacers on opposing walls of the first metal gate, and a second pair of gate spacer on opposing sidewalls of the second metal gate; and
a first pair of outer spacers on opposing sidewalls of the first pair of gate spacers, and a second pair of outer spacers on opposing sidewalls of the second pair of gate spacers.
15. The semiconductor device of claim 14 , wherein the first metal gate does not extend laterally over the first pair of outer spacers and the second metal gate does not extend laterally over the second pair of outer spacers.