Semiconductor device having a field effect transistor formed on a silicon-on-insulator substrate and manufacturing method thereof

1. A semiconductor device, comprising:

a semiconductor substrate; and

first and second field effect transistors,

wherein the semiconductor substrate has:

a first base substrate including a first region and a second region;

a first semiconductor region of a first conductivity type formed on the first region of the first base substrate or in an upper layer part of the first region of the first base substrate;

an insulating layer formed on the first semiconductor region; and

a semiconductor layer formed on the insulating layer,

wherein the first base substrate is made of silicon,

wherein the first semiconductor region is made of silicon carbide,

wherein the first field effect transistor is formed on the semiconductor layer,

wherein the semiconductor layer, the insulating layer, and the first semiconductor region are removed from the second region, and

wherein the second field effect transistor is formed on the second region of the first base substrate.

2. The semiconductor device according to claim 1 ,

wherein the first semiconductor region is epitaxially grown on the first base substrate.

3. The semiconductor device according to claim 1 ,

wherein a first impurity of the first conductivity type is introduced to the first semiconductor region,

a concentration distribution of the first impurity in a thickness direction of the first semiconductor region has a peak between an upper surface of the first semiconductor region and a lower surface of the first semiconductor region, and

both of a concentration of the first impurity of the upper surface of the first semiconductor region and a concentration of the first impurity of the lower surface of the first semiconductor region are lower than a half of a concentration of the first impurity at the peak.

4. The semiconductor device according to claim 1 ,

wherein the first field effect transistor has:

a first gate electrode formed on the semiconductor layer via a first gate insulating film;

a second semiconductor region of a second conductivity type opposite to the first conductivity type formed in a part of the semiconductor layer located on a first side of the first gate electrode; and

a third semiconductor region of the second conductivity type formed in a part of the semiconductor layer located on a side opposite to the first side of the first gate electrode, and

wherein the second field effect transistor has:

a second gate electrode formed on the second region of the first base substrate via a second gate insulating film;

a fourth semiconductor region of the second conductivity type formed in a part of the second region of the first base substrate located on a first side of the second gate electrode; and

a fifth semiconductor region of the second conductivity type formed in a part of the second region of the first base substrate located on a side opposite to the first side of the second gate electrode.

5. The semiconductor device according to claim 4 ,

wherein a second impurity of the first conductivity type is introduced to the first semiconductor region,

the first conductivity type is a p type,

the second conductivity type is an n type, and

the second impurity is made of boron.

6. The semiconductor device according to claim 1 ,

wherein the semiconductor substrate has a fourth semiconductor region formed on the first semiconductor region,

the insulating layer is formed on the first semiconductor region via the fourth semiconductor region, and

the fourth semiconductor region is made of silicon.

7. A manufacturing method of a semiconductor device, comprising:

(a) preparing a first semiconductor substrate;

(b) forming a first field effect transistor; and

(c) forming a second field effect transistor,

wherein the first semiconductor substrate prepared in (a) has:

a first base substrate including a first region and a second region,

a first semiconductor region formed on the first base substrate or in an upper layer part of the first base substrate,

an insulating layer formed on the first semiconductor region, and

a semiconductor layer formed on the insulating layer,

wherein, in (b), a first impurity of a first conductivity type is introduced to the first semiconductor region formed on the first region of the first base substrate,

wherein, in (c), respective portions of the semiconductor layer, the insulating layer, and the first semiconductor region that were formed on the second region of the first base substrate are removed therefrom,

wherein the first field effect transistor is formed on the semiconductor layer,

wherein the second field effect transistor is formed on the second region of the first base substrate,

wherein the first base substrate is made of silicon, and

wherein the first semiconductor region is made of silicon carbide.

8. The manufacturing method of a semiconductor device according to claim 7 ,

wherein (a) includes:

(a1) epitaxially growing the first semiconductor region on the first base substrate; and

(a2) transferring a stacked body made up of the insulating layer and the semiconductor layer disposed on the insulating layer onto the first semiconductor region.

9. The manufacturing method of a semiconductor device according to claim 7 ,

wherein a concentration distribution of the first impurity introduced in (b) in a thickness direction of the first semiconductor region has a peak between an upper surface of the first semiconductor region and a lower surface of the first semiconductor region, and

both of a concentration of the first impurity of the upper surface of the first semiconductor region and a concentration of the first impurity of the lower surface of the first semiconductor region are lower than a half of a concentration of the first impurity at the peak.

10. The manufacturing method of a semiconductor device according to claim 7 ,

wherein (b) includes:

(b1) forming a first gate electrode on the semiconductor layer via a first gate insulating film; and

(b2) forming a second semiconductor region of a second conductivity type opposite to the first conductivity type in a part of the semiconductor layer located on a first side of the first gate electrode and forming a third semiconductor region of the second conductivity type in a part of the semiconductor layer located on a side opposite to the first side of the first gate electrode, and

wherein (c) includes:

(c1) forming a second gate electrode on the second region of the first base substrate via a second gate insulating film; and

(c2) forming a fourth semiconductor region of the second conductivity type in a part of the second region of the first base substrate located on a first side of the second gate electrode, and forming a fifth semiconductor region of the second conductivity type in a part of the second region of the first base substrate located on a side opposite to the first side of the second gate electrode.

11. The manufacturing method of a semiconductor device according to claim 10 ,

wherein the first conductivity type is a p type,

the second conductivity type is an n type, and

the first impurity is made of boron.

12. The manufacturing method of a semiconductor device according to claim 7 ,

wherein (b) includes:

(b3) ion-implanting the first impurity into the first semiconductor region.

13. The manufacturing method of a semiconductor device according to claim 12 ,

wherein (b) includes:

(b4) performing a thermal treatment to the first semiconductor substrate at a first temperature after (b3), and

the first temperature is 800° C. or higher.

14. The manufacturing method of a semiconductor device according to claim 7 ,

wherein, in (a), the first semiconductor substrate having a fourth semiconductor region formed on the first semiconductor region and the insulating layer formed on the first semiconductor region via the fourth semiconductor region is prepared, and

the fourth semiconductor region is made of silicon.

15. The manufacturing method of a semiconductor device according to claim 8 ,

wherein, in (a1), a second semiconductor substrate made up of the first base substrate and the first semiconductor region is prepared, and

wherein (a2) includes:

(a3) preparing a third semiconductor substrate made up of a second base substrate made of a semiconductor and the insulating layer formed on the second base substrate;

(a4) bonding the third semiconductor substrate onto the second semiconductor substrate in a state where the insulating layer faces the first semiconductor region after (a1) and (a3); and

(a5) leaving the insulating layer and a surface layer part of the second base substrate on a side close to the second semiconductor substrate on the second semiconductor substrate and removing the second base substrate other than the surface layer part from the second semiconductor substrate after (a4).

16. The semiconductor device of claim 4 ,

wherein the first field effect transistor has a first semiconductor film on the second semiconductor region and a second semiconductor film on the third semiconductor region,

wherein the first and second semiconductor films have the second conductivity type,

wherein an impurity concentration of the first semiconductor film is greater than that of the second semiconductor region, and

wherein an impurity concentration of the second semiconductor film is greater than that of the third semiconductor region.

17. The semiconductor device of claim 1 ,

wherein the first base substrate further includes a third region between the first and second regions in plan view,

wherein the first, second, and third regions are separated from each other by trenches extending into the first base substrate and filled with insulating material, and

wherein a contact for applying a voltage bias to the first semiconductor region is formed on the third region.

18. The semiconductor device of claim 17 , wherein the semiconductor layer, the insulating layer, and the first semiconductor region are also removed from the third region.

19. The semiconductor device of claim 17 , further comprising a well region of the first conductivity type formed in the first base substrate and extending between the first and third regions to electrically connect the contact with the first semiconductor region.