Semiconductor device with enhanced orientation ratio and method of manufacturing same
View Patent ↗An object is to enhance the orientation ratio of a crystalline semiconductor film obtained by crystallizing an amorphous semiconductor film while using as a substrate a less-heat-resistive material such as glass thereby providing a semiconductor device using a crystalline semiconductor film with high quality equivalent to a single crystal. A first crystalline semiconductor film and a second crystalline semiconductor film are formed overlying a substrate, which integrally structure a crystalline semiconductor layer. The first and second crystalline semiconductor films are polycrystalline bodies aggregated with a plurality of crystal grains. However, the crystal grains are aligned toward a (101)-plane orientation at a ratio of 30 percent or greater, preferably 80 percent or greater. Also, relying on a plane orientation of the crystal grains in the first crystalline semiconductor film, the second crystalline semiconductor film has a plane orientation also aligned in the same direction with a probability of 60 percent or higher.
1. A semiconductor device comprising:
a first crystalline semiconductor film comprising silicon added with an element having an atomic radius greater than silicon over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with the first crystalline semiconductor film;
wherein the first semiconductor film has a semiconductor region having a (101)-plane orientation ratio of 30 percent or greater, and
wherein the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
2. A semiconductor device according to claim 1 , wherein the element having an atomic radius greater than silicon is germanium.
3. A semiconductor device comprising:
a first crystalline semiconductor film comprising silicon and germanium over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with the first crystalline semiconductor film;
wherein the first crystalline semiconductor film has a (101)-plane orientation ratio of 30 percent or greater, and
wherein the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
4. A semiconductor device according to claim 3 , wherein at least one of oxygen, carbon and nitrogen having a concentration of 1×10 19 /cm 3 or higher is contained between the first crystalline semiconductor film and the second crystalline semiconductor film.
5. A semiconductor device comprising:
a first crystalline semiconductor film containing silicon and germanium over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with the first crystalline semiconductor film;
wherein the second crystalline semiconductor film has a (101)-plane orientation ratio of 20 percent or greater, and
the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
6. A semiconductor device according to claim 5 , wherein at least one of oxygen, carbon and nitrogen having a concentration of 1×10 19 /cm 3 or higher is contained between the first crystalline semiconductor film and the second crystalline semiconductor film.
7. A semiconductor device comprising:
a first crystalline semiconductor film comprising silicon and germanium over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with the first crystalline semiconductor film;
wherein the first crystalline semiconductor film has a (101)-plane orientation ratio of 30 percent or greater and the second crystalline semiconductor film has a (101)-plane orientation ratio of 20 percent or greater, and
wherein the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
8. A semiconductor device according to claim 7 , wherein the first crystalline semiconductor film contains germanium in a concentration of 1×10 20 /cm 3 or less.
9. A semiconductor device according to claim 7 , wherein the second crystalline semiconductor film contains germanium in a concentration of 1×10 19 /cm 3 or less.
10. A semiconductor device according to claim 7 , wherein at least one of oxygen, carbon and nitrogen having a concentration of 1×10 19 /cm 3 or higher is contained between the first crystalline semiconductor film and the second crystalline semiconductor film.
11. A semiconductor device comprising:
a first crystalline semiconductor film comprising silicon and germanium over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with the first crystalline semiconductor film;
wherein the first crystalline semiconductor film contains germanium in a concentration of 1×10 20 /cm 3 or less,
wherein the second crystalline semiconductor film has a (101)-plane orientation ratio of 20 percent or greater, and
wherein the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
12. A semiconductor device according to claim 11 , wherein the second crystalline semiconductor film contains germanium in a concentration of 1×10 19 /cm 3 or less.
13. A semiconductor device according to claim 11 , wherein at least one of oxygen, carbon and nitrogen having a concentration of 1×10 19 /cm 3 or higher is contained between the first crystalline semiconductor film and the second crystalline semiconductor film.
14. A semiconductor device comprising:
a first crystalline semiconductor film comprising silicon and germanium over a substrate; and
a second crystalline semiconductor film comprising silicon over and in contact with a first crystalline semiconductor film;
wherein the second crystalline semiconductor film contains germanium in a concentration of 1×10 19 /cm 3 or less,
wherein the second crystalline semiconductor film has a (101)-plane orientation ratio of 20 percent or greater, and
wherein the first crystalline semiconductor film and the second crystalline semiconductor film are coincident in crystal orientation at a ratio of 60 percent or higher.
15. A semiconductor device according to claim 14 , wherein at least one of oxygen, carbon and nitrogen having a concentration of 1×10 19 /cm 3 or higher is contained between the first crystalline semiconductor film and the second crystalline semiconductor film.