METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE
A protection film is formed on a semiconductor substrate. Impurity ions are implanted into the semiconductor substrate through the protection film. The impurity is activated to form an impurity layer. The protection film is removed after forming the impurity layer. The semiconductor substrate of a surface portion of the impurity layer is removed after removing the protection film. A semiconductor layer is epitaxially grown above the semiconductor substrate after removing the semiconductor substrate of the surface portion of the impurity layer.
1 . A method of manufacturing a semiconductor device comprising:
forming a protection film above a semiconductor substrate;
forming an impurity layer in the semiconductor substrate by ion implanting an impurity in the semiconductor substrate through the protection film;
removing the protection film after forming the impurity layer;
removing at least silicon that is component of a surface portion, that includes the impurity layer, of the semiconductor substrate after removing the protection film;
epitaxially growing a semiconductor layer above the semiconductor substrate after removing at least silicon;
forming a gate insulating film above the semiconductor layer;
forming a gate electrode above the gate insulating film; and
after forming the gate electrode, forming a source/drain region in the semiconductor layer,
wherein the semiconductor device includes a transistor having a first region in the semiconductor layer below the gate insulating film with a first impurity concentration, and a second region in the semiconductor layer below the first region with a second impurity concentration which is higher than the first impurity concentration,
wherein constituent atoms of the protection film pushed into the semiconductor substrate upon ion implanting the impurity is removed in removing at least silicon.
2 . The method of manufacturing a semiconductor device according to claim 1 , wherein removing the protection film includes wet etching with a first solution, and removing at least silicon that is component of the surface portion includes wet etching with a second solution is different from the first solution.
3 . The method of manufacturing a semiconductor device according to claim 2 , wherein the first solution is a hydrofluoric acid aqueous solution, and the second solution is a solution of tetra-methyl ammonium hydroxide.
4 . The method of manufacturing a semiconductor device according to claim 1 , wherein an etching thickness of the semiconductor substrate is from 3 nm to 5 nm in removing at least silicon.
5 . The method of manufacturing a semiconductor device according to claim 1 , wherein a concentration of the constituent atoms removed in the removing at least silicon is about 9/10 of a concentration of the constituent atoms pushed into the semiconductor substrate by the ion implanting.
6 . A method of manufacturing a semiconductor device comprising:
forming a protection film above a semiconductor substrate;
forming an impurity layer in the semiconductor substrate by ion implanting an impurity in the semiconductor substrate through the protection film;
removing the protection film after forming the impurity layer;
removing at least silicon that is component of a surface portion, that includes the impurity layer, of the semiconductor substrate after removing the protection film;
epitaxially growing a semiconductor layer above the semiconductor substrate after removing at least silicon;
forming a gate insulating film above the semiconductor layer;
forming a gate electrode above the gate insulating film; and
after forming the gate electrode, forming a source/drain region in the semiconductor layer,
wherein the semiconductor device includes a transistor having a first region in the semiconductor layer below the gate insulating film with a first impurity concentration, and a second region in the semiconductor layer below the first region with a second impurity concentration which is higher than the first impurity concentration,
wherein, oxygen is pushed into the semiconductor substrate by the ion implanting in the forming the impurity layer, and the oxygen, that is pushed into the semiconductor substrate, is removed in the removing at least silicon.
7 . The method of manufacturing a semiconductor device according to claim 6 , wherein removing the protection film includes wet etching with a first solution, and removing at least silicon that is component of the surface portion includes wet etching with a second solution that is different from the first solution.
8 . The method of manufacturing a semiconductor device according to claim 7 , wherein the first solution is a hydrofluoric acid aqueous solution, and the second solution is a solution of tetra-methyl ammonium hydroxide.
9 . The method of manufacturing a semiconductor device according to claim 6 , wherein an etching thickness of the semiconductor substrate is from 3 nm to 5 nm in removing at least silicon.
10 . The method of manufacturing a semiconductor device according to claim 6 , wherein a concentration of the oxygen removed in the removing at least silicon is about 9/10 of a concentration of the oxygen pushed into the semiconductor substrate by the ion implanting.