JP2010278120A5

JP2010278120A5 -

Info

Publication number: JP2010278120A5
Application number: JP2009127576A
Authority: JP
Filing date: 2009-05-27
Publication date: 2011-12-22
Anticipated expiration: 2029-05-27

Description

上記目的を達成するために、この発明は、所定のオフ角を有する炭化珪素基板の表面上に、活性領域となる所定のＣ／Ｓｉ比を有する第１の炭化珪素層を形成する第１工程と、前記第１の炭化珪素層の表面上に、前記所定のＣ／Ｓｉ比より小さく、かつ、表面が平坦となるＣ／Ｓｉ比を有する第２の炭化珪素層を形成する第２工程と、前記第２の炭化珪素層をエッチング除去する第３工程とを備えている。 To achieve the above object, the present invention provides a first step of forming a first silicon carbide layer having a predetermined C / Si ratio to be an active region on a surface of a silicon carbide substrate having a predetermined off angle. And forming a second silicon carbide layer having a C / Si ratio smaller than the predetermined C / Si ratio and having a flat surface on the surface of the first silicon carbide layer; And a third step of etching away the second silicon carbide layer.

以上の説明から明らかなように、この発明によれば、活性領域となる所定のＣ／Ｓｉ比を有する第１の炭化珪素層の表面上に、所定のＣ／Ｓｉ比より小さく、かつ、表面が平坦となるＣ／Ｓｉを有する第２の炭化珪素層を形成した後に、この第２の炭化珪素層をエッチング除去するようにした。これにより、第１の炭化珪素層表面に生じるステップバンチング部が除去されるので、凹凸の大きいステップバンチングに対しても平坦化可能であり、また平坦化にあたりＣＭＰ研磨などの研磨装置及び研磨工程も必要としないのでコスト増加も抑制することができる。 As is apparent from the above description, according to the present invention, the surface of the first silicon carbide layer having a predetermined C / Si ratio serving as the active region is smaller than the predetermined C / Si ratio and has a surface After the second silicon carbide layer having C / Si that becomes flat is formed, the second silicon carbide layer is removed by etching. Thereby, since the step bunching portion generated on the surface of the first silicon carbide layer is removed, it is possible to flatten even for step bunching with large unevenness, and a polishing apparatus such as CMP polishing and a polishing process are also required for the flattening. Since it is not necessary, an increase in cost can be suppressed.

Claims

A first step of forming a first silicon carbide layer having a predetermined C / Si ratio to be an active region on a surface of a silicon carbide substrate having a predetermined off angle ;
Before SL on the surface of the first silicon carbide layer, wherein less than a predetermined C / Si ratio, and a second step of forming a second silicon carbide layer having a C / Si ratio the surface becomes flat,
A third step of etching away the previous SL second silicon carbide layer,
A method for manufacturing a silicon carbide semiconductor device comprising:

C / Si ratio of forming the second silicon carbide layer is 0.8 or less,
Manufacturing method of the preceding Symbol silicon carbide semiconductor device of temperature according to claim 1, wherein at 1600 ° C. or less to form a second silicon carbide layer.

C / Si ratio of forming the second silicon carbide layer is Ru 0.5 der
請 Motomeko 2 method for manufacturing the silicon carbide semiconductor device according.

The C / Si ratio forming the first silicon carbide layer is 1.5 or more,
The temperature for forming the second silicon carbide layer is not less than 1550 ° C. and not more than 1650 ° C.
The manufacturing method of the silicon carbide semiconductor device of any one of Claims 1 thru | or 3.

The predetermined off angle is 5 degrees or less with respect to the (0001) plane.
The manufacturing method of the silicon carbide semiconductor device of any one of Claims 1 thru | or 4.

The third step of etching away the second silicon carbide layer includes:
Performed by dry etching using hydrogen gas
The manufacturing method of the silicon carbide semiconductor device of any one of Claims 1 thru | or 5.

The third step of etching away the second silicon carbide layer includes:
A step 3a of replacing the entire second silicon carbide layer with a sacrificial oxide film by thermal oxidation;
A 3b step of removing the sacrificial oxide film by wet etching using hydrofluoric acid;
The manufacturing method of the silicon carbide semiconductor device of any one of Claims 1 thru | or 5 containing these.

The third step of etching away the second silicon carbide layer includes:
A step 3a of replacing a part of the second silicon carbide layer with a sacrificial oxide film by a thermal oxidation method;
A 3b step of removing the sacrificial oxide film by wet etching using hydrofluoric acid;
6. The method of manufacturing a silicon carbide semiconductor device according to claim 1, wherein the step 3a and the step 3b are repeated until the second silicon carbide layer is removed.

The third step of etching away the second silicon carbide layer includes:
In addition to the second silicon carbide layer, step bunching formed on the surface of the first silicon carbide layer is also removed.
A method for manufacturing a silicon carbide semiconductor device according to any one of claims 1, 6 to 8.