Semiconductor device and method for manufacturing the same

1. A semiconductor device comprising:

a silicon substrate having a first plane with a first plane orientation;

a silicon oxide layer provided on a first region of the silicon substrate;

a first silicon layer provided on the silicon oxide layer, the first silicon layer having a second plane with a second plane orientation different from the first plane orientation;

a wide-bandgap compound semiconductor layer having a hexagonal crystal structure; and

a second silicon layer provided on a second region of the silicon substrate, the second region being different from the first region,

wherein the wide-bandgap compound semiconductor layer is provided on the first silicon layer,

the first plane orientation is {100},

the second plane orientation is {111} and,

the first silicon layer is undoped.

2. The semiconductor device according to claim 1 ,

wherein the wide-bandgap compound semiconductor layer includes a nitride semiconductor.

3. The semiconductor device according to claim 1 ,

wherein the wide-bandgap compound semiconductor layer includes silicon carbide.

4. The semiconductor device according to claim 1 , further comprising:

a first source electrode, a first drain electrode and a first gate electrode provided on the wide-bandgap compound semiconductor layer,

wherein the first gate electrode is provided between the first source electrode and the first drain electrode.

5. The semiconductor device according to claim 1 , further comprising:

an element isolation layer provided between the second silicon layer, and the silicon oxide layer, the first silicon layer, and the wide-bandgap compound semiconductor layer.

6. The semiconductor device according to claim 1 , further comprising:

an n-type source region provided on the second silicon layer;

an n-type drain region provided on the second silicon layer;

a second source electrode provided on the source region;

a second drain electrode provided on the drain region;

a gate insulating film provided between the second source electrode and the second drain electrode; and

a second gate electrode provided on the gate insulating film,

wherein the second silicon layer is a p type.

7. The semiconductor device according to claim 1 , further comprising:

a first source electrode, a first drain electrode and a first gate electrode provided on the wide-bandgap compound semiconductor layer;

an n-type source region provided on the second silicon layer;

an n-type drain region provided on the second silicon layer;

a second source electrode provided on the source region;

a second drain electrode provided on the drain region;

a gate insulating film provided between the second source electrode and the second drain electrode; and

a second gate electrode provided on the gate insulating film,

wherein the second silicon layer is a p type,

the first gate electrode is provided between the first source electrode and the first drain electrode,

the first gate electrode is electrically connected to the second source electrode, and

the first source electrode is electrically connected to the second drain electrode.

8. A semiconductor device comprising:

a silicon substrate having a first plane with a first plane orientation;

a silicon oxide layer provided on a first region of the silicon substrate;

a first silicon layer provided on the silicon oxide layer, the first silicon layer having a second plane with a second plane orientation different from the first plane orientation; and

a wide-bandgap compound semiconductor layer having a hexagonal crystal structure;

wherein the wide-bandgap compound semiconductor layer is provided on a second region of the silicon substrate, the second region being different from the first region,

the first plane orientation is {111},

the second plane orientation is {100}, and

the second region of the silicon substrate is undoped.

9. The semiconductor device according to claim 8 , further comprising:

a first source electrode, a first drain electrode and a first gate electrode provided on the wide-bandgap compound semiconductor layer;

an n-type source region provided on the first silicon layer;

an n-type drain region provided on the first silicon layer;

a second source electrode provided on the source region;

a second drain electrode provided on the drain region;

a gate insulating film provided between the second source electrode and the second drain electrode; and

a second gate electrode provided on the gate insulating film,

wherein the second silicon layer is a p type,

the first gate electrode is provided between the first source electrode and the first drain electrode,

the first gate electrode is electrically connected to the second source electrode, and

the first source electrode is electrically connected to the second drain electrode.

10. The semiconductor device according to claim 8 , further comprising:

an element isolation layer provided between the wide-bandgap compound semiconductor layer, and the silicon oxide layer and the first silicon layer.

11. The semiconductor device according to claim 8 , further comprising:

an n-type source region provided on the first silicon layer;

an n-type drain region provided on the first silicon layer;

a third source electrode provided on the source region;

a third drain electrode provided on the drain region;

a gate insulating film provided between the third source electrode and the third drain electrode; and

a third gate electrode provided on the gate insulating film, wherein the first silicon layer is a p type.