Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device includes a semiconductor layer formed by epitaxial growth in a first region which is obtained by etching a semiconductor substrate to a predetermined depth, a surface of the semiconductor layer having a same height from the bottom of the semiconductor substrate as a height of a surface of the semiconductor substrate, a buried insulating layer buried between the semiconductor substrate and the semiconductor layer and an element isolation region separating each element region in the semiconductor layer and isolating the semiconductor layer from the semiconductor substrate in plan.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 shows an arrangement of regions on a substrate of a semiconductor device according to an embodiment of the invention.

FIGS. 2A through 2D show a step in a method of manufacturing a semiconductor device according to a first embodiment of the invention.

FIGS. 3A through 3D show a step in the method of manufacturing a semiconductor device according to the first embodiment of the invention.

FIGS. 4A through 4D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 5A through 5D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 6A through 6D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 7A through 7D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 8A through 8D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 9A through 9D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 10A through 10D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 11A through 11D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 12A through 12D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 13A through 13D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 14A through 14D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 15A through 15D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIGS. 16A through 16D show a step in the method of manufacturing a semiconductor device according to the first embodiment.

FIG. 17 shows a step in a method of manufacturing a semiconductor device according to a second embodiment of the invention.

FIG. 18 shows a step in the method of manufacturing a semiconductor device according to the second embodiment of the invention.

FIG. 19 shows a step in the method of manufacturing a semiconductor device according to the second embodiment of the invention.

FIG. 20 shows a step in the method of manufacturing a semiconductor device according to the second embodiment.

Claims

1. A semiconductor device, comprising: a semiconductor layer formed by epitaxial growth in a first region which is obtained by etching a semiconductor substrate to a predetermined depth, a surface of the semiconductor layer having a same height from the bottom of the semiconductor substrate as a height of a surface of the semiconductor substrate;a buried insulating layer buried between the semiconductor substrate and the semiconductor layer; andan element isolation region separating each element region in the semiconductor layer and isolating the semiconductor layer from the semiconductor substrate in plan.

2. A method of manufacturing a semiconductor device on a semiconductor substrate that has a first element region having a silicon-on-insulator structure (SOI) structure, a second element region having a bulk structure and an element isolation region separating each region, the first region and the second region being provided in a plural number, the method comprising: etching a part of a first area situated next to the first element region in the first element region and/or the element isolation region on the semiconductor substrate to a predetermined depth;forming a mask layer in an unetched second area other than the etched first area;forming a first semiconductor layer made of an material that has a larger etching rate than an etching rate of the semiconductor substrate selectively in an unmasked area;forming a second semiconductor layer made of an material that has a smaller etching rate than the etching rate of the first semiconductor layer on the first semiconductor layer;forming a first groove in an third area where the first semiconductor layer and the second semiconductor layer are formed in the element isolation region, the first groove penetrating the first semiconductor layer and the second semiconductor layer and exposing the semiconductor substrate;forming a supporting layer in the first groove and in at least a part of the first element region, the supporting layer supporting the second semiconductor layer on the semiconductor substrate;forming a second groove in the element isolation region except an area where the first groove is formed, the second groove exposing the first semiconductor layer;forming a cavity under the second semiconductor layer by removing the first semiconductor layer by etching the first semiconductor layer through the second groove; andforming a buried insulating layer embedded in the cavity through the second groove.

3. The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor substrate is exposed at the bottom of the second groove when the second groove is formed.

4. The method of manufacturing a semiconductor device according to claim 2, wherein a third groove is simultaneously formed in the element isolation region that separates each region in the second element region when the second groove exposing the first semiconductor layer is formed.

5. The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor substrate is etched to a depth substantially same as a sum of thicknesses of the first semiconductor layer and the second semiconductor layer when the part of the first area is etched.

6. The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor substrate is a single-crystalline semiconductor substrate, and the first semiconductor layer and the second semiconductor layer is a single-crystalline semiconductor layer formed by epitaxial growth.

7. The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor substrate and the second semiconductor layer are made of single-crystalline silicon, and the first semiconductor layer is made of a single-crystalline silicon germanium.

8. The method of manufacturing a semiconductor device according to claim 2 wherein an insulating film is formed on the second semiconductor layer before the first groove is formed.

9. The method of manufacturing a semiconductor device according to claim 8, wherein the insulating layer includes at least a silicon nitride film.

10. A method of manufacturing a semiconductor device on a semiconductor substrate that has a first element region having a silicon-on-insulator structure (SOI) structure, a second element region having a bulk structure and an element isolation region separating each element region, the first region and the second region being provided in a plural number, the method comprising: forming a mask in the second element region on the semiconductor substrate;etching a part of a first area situated next to the first element region in the first element region and/or the element isolation region to a predetermined depth;forming a first semiconductor layer made of an material that has a larger etching rate than an etching rate of the semiconductor substrate on the semiconductor substrate and the mask;forming a second semiconductor layer made of an material that has a smaller etching rate than the etching rate of the first semiconductor layer on the first semiconductor layer;removing the first semiconductor layer and the second semiconductor layer that exit in an unetched area;forming a first groove in an second area where the first semiconductor layer and the second semiconductor layer are formed in the element isolation region, the first groove penetrating the first semiconductor layer and the second semiconductor layer and exposing the semiconductor substrate;forming a supporting layer in the first groove and in at least a part of the first element region, the supporting layer supporting the second semiconductor layer on the semiconductor substrate;forming a second groove in the element isolation region except an area where the first groove is formed, the second groove exposing the first semiconductor layer;forming a cavity under the second semiconductor layer by removing the first semiconductor layer by etching the first semiconductor layer through the second groove; andforming a buried insulating layer embedded in the cavity through the second groove.

11. The method of manufacturing a semiconductor device according to claim 10, wherein the semiconductor substrate is exposed at the bottom of the second groove when the second groove is formed.

12. The method of manufacturing a semiconductor device according to claim 10, wherein a third groove is simultaneously formed in the element isolation region that separates each region in the second element region when the second groove exposing the first semiconductor layer is formed.

13. The method of manufacturing a semiconductor device according to claim 10, wherein the semiconductor substrate is etched to a depth substantially same as a sum of thicknesses of the first semiconductor layer and the second semiconductor layer when the part of the first area is etched.

14. The method of manufacturing a semiconductor device according to claim 10, wherein the semiconductor substrate is a single-crystalline semiconductor substrate, and the first semiconductor layer and the second semiconductor layer is a single-crystalline semiconductor layer formed by epitaxial growth.

15. The method of manufacturing a semiconductor device according to claim 10, wherein the semiconductor substrate and the second semiconductor layer are made of single-crystalline silicon, and the first semiconductor layer is made of a single-crystalline silicon germanium.

16. The method of manufacturing a semiconductor device according to claim 10, wherein an insulating film is formed on the second semiconductor layer before the first groove is formed.

17. The method of manufacturing a semiconductor device according to claim 16, wherein the insulating layer includes at least a silicon nitride film.