Semiconductor device

1. A semiconductor device comprising: a plurality of semiconductor elements formed on a silicon substrate, a first one of the semiconductor elements having a region formed with a surface orientation of <100>, a second one of the semiconductor elements having a region formed with a surface orientation of <110>or <111>, and a third one of the semiconductor elements having a region formed with a surface orientation different from the respective surface orientations of the regions of the first and second semiconductor elements.

2. A semiconductor device according to claim 1 ; further comprising a silicon oxide film formed on the silicon substrate; and wherein at least a part of a boundary surface between the silicon substrate and the silicon oxide film used to pass electrons and holes therethrough is formed with the same surface orientation as that of the region of the third semiconductor element.

3. A semiconductor device according to claim 2 ; wherein the boundary surface between the silicon substrate and the silicon oxide film is inclined by 1 to 4 degrees from the <100>surface orientation toward a surface orientation of <010>.

4. A semiconductor device according to claim 1 ; wherein the surface orientation of the region of the third semiconductor element is inclined by 1 to 4 degrees from the <100>surface orientation toward a surface orientation of <010>.

5. A semiconductor device comprising:

an NMOS transistor formed on a silicon substrate and having a channel region formed with a surface orientation of <100>;

a PMOS transistor formed on the silicon substrate and having a channel region formed with a surface orientation of <110>or <111>; and

a MOS capacitor formed on the silicon substrate and having a gate electrode and at least a region just below the gate electrode that is formed with a surface orientation different from that of the channel region of each of the NMOS transistor and the PMOS transistor.

6. A semiconductor device according to claim 5 ; further comprising a silicon oxide film formed on the silicon substrate; and wherein at least a part of a boundary surface between the silicon substrate and the silicon oxide film used to pass electrons and holes therethrough is formed with the same surface orientation as that of the region of the MOS capacitor.

7. A semiconductor device according to claim 6 ; wherein the boundary surface between the silicon substrate and the silicon oxide film is inclined by 1 to 4 degrees from the <100>surface orientation toward a surface orientation of <010>.

8. A semiconductor device according to claim 5 ; wherein the surface orientation of the region of the MOS capacitor is inclined by 1 to 4 degrees from the <100>surface orientation toward a surface orientation of <010>.

9. A semiconductor device comprising: an NMOS transistor having a channel region formed with a surface orientation of <100>; a PMOS transistor having a channel region formed with a surface orientation of <110>or <111>; and a memory cell having a region formed with a surface orientation that is inclined by 1 to 4 degrees from the <100>surface orientation toward a surface orientation of <010>.

10. A semiconductor device according to claim 9 ; wherein the region of the memory cell comprises a formation region of a tunnel oxide film of the memory cell.

11. A semiconductor device according to claim 10 ; wherein the tunnel oxide film comprises a silicon oxide film.

12. A semiconductor device according to claim 9 ; wherein the region of the memory cell comprises at least a boundary surface of a gate oxide film in a drain end portion in which electric charges are exchanged.