Claims
- 1. A method for preparing semiconductor devices, which comprises the steps of forming a layer of a substance acting as an etching mask on a substrate having a surface on the (100) crystal plane or on a plane inclined within 5.degree. against the (100) crystal plane, opening on said substrate layer a window having a polygonal shape having main sides parallel to at least one specific direction selected from the direction of the <100> crystal axis and directions inclined within 25.degree. against the <100> crystal axis, thereby forming an etching mask, etching the interior of said window with an anisotropic etching solution, thereby forming a substrate having a dent, removing said etching mask, epitaxially growing a semiconductor layer on the entire surface of said substrate while filling up said dent, masking a secondary dent formed by transfer of said dent of the substrate on said epitaxially grown semiconductor layer with a layer of a substance acting as an etching mask, and etching said semiconductor layer with an anisotropic etching solution to flatten the surface thereof.
- 2. A method for preparing semiconductor devices according to claim 1 wherein said window has a polygonal shape having main sides parallel to the direction of the <100> crystal axis.
- 3. A method for preparing semiconductor devices according to claim 1 wherein said substrate is a silicon substrate of one conductor type and said epitaxially grown semiconductor layer is an epitaxial silicon layer of a conductor type opposite to that of the substrate.
- 4. A method for preparing semiconductor devices according to claim 3 wherein the anisotropic etching solution is an alkaline etching solution.
- 5. A method for preparing semiconductor devices according to claim 4 wherein the alkaline etching solution is selected from KOH type, NaOH type, hydrazine type, ethylene diamine type and ammonia type etching solutions.
- 6. A method for preparing semiconductor devices according to claim 3 wherein the substance acting as the etching mask is a silicon oxide film.
- 7. A method for preparing semiconductor devices according to claim 1, wherein a mask on said secondary dent covers a bottom and side walls of said secondary dent and extends on a portion surrounding said secondary dent.
- 8. A method for preparing semiconductor devices according to claim 1, wherein said dent is formed to have sides extending in a direction parallel to the <100> crystal axis or inclined within 25.degree. against the <100> crystal axis.
- 9. A method for preparing semiconductor devices according to claim 1, wherein said substrate has a surface on a plane inclined 3.degree. to 5.degree. against the (100) crystal plane.
- 10. A method for preparing semiconductor devices according to claim 3, further comprising the steps of forming a first highly doped layer of said opposite conductivity type on a bottom, side walls and a surrounding portion of said dent, and forming a second highly doped layer of said opposite conductivity type extending from a surface of said epitaxially grown semiconductor layer to the surrounding portion of said dent.
Priority Claims (3)
Number |
Date |
Country |
Kind |
52-123474 |
Oct 1977 |
JPX |
|
52-173999 |
Dec 1977 |
JPX |
|
53-103944 |
Aug 1978 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 950,671, filed Oct. 12, 1978, U.S. Pat. No. 4,278,987.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4089021 |
Sato et al. |
May 1978 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
52-43369 |
Apr 1977 |
JPX |
7610970 |
Apr 1977 |
NLX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
950671 |
Oct 1978 |
|