Sumitomo Electric Industries, Limited

Hironori Itoh

Keiji Wada

Taro Nishiguchi

Tsutomu Hori

Hideyuki Doi

Jun Genba

Tomoaki Hatayama

Kenji Kanbara

Takemi Terao

When a value obtained by dividing the number of the one or more second regions by a total of the number of the one or more first regions and the number of the one or more second regions is defined as a first defect free area ratio, a value obtained by dividing the number of the one or more fourth regions by a total of the number of the one or more third regions and the number of the one or more fourth regions is defined as a second defect free area ratio, and a value obtained by dividing the number of the one or more macroscopic defects by an area of the central region is defined as X cm, A is smaller than B, B is less than or equal to 4, X is more than 0 and less than 4, and a Formula 1 is satisfied.

Silicon carbide epitaxial substrate and method for manufacturing silicon carbide semiconductor device

In a step of calculating formation conditions for the second silicon carbide layer, a formation time of the second silicon carbide layer is calculated as a value obtained by multiplying a value obtained by dividing the second thickness by the first thickness, by the first formation time, and a flow rate of a second ammonia gas in a step of forming the second silicon carbide layer by epitaxial growth is calculated as a value obtained by multiplying a value obtained by dividing the second concentration by the first concentration, by the first flow rate.

Method for manufacturing silicon carbide epitaxial substrate

A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1&#xd7;10cmand not more than 5&#xd7;10cm. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a grooveextending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.

Silicon carbide epitaxial substrate having grooves extending along main surface and method of manufacturing silicon carbide semiconductor device

A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. A first ratio of an absolute value of a difference between a dopant density in a first end region and a dopant density in a central region to an average value of the dopant density in the first end region and the dopant density in the central region is not more than 40%. A second ratio of an absolute value of a difference between a dopant density in a second end region and the dopant density in the central region to an average value of the dopant density in the second end region and the dopant density in the central region is not more than 40%.

Silicon carbide epitaxial substrate and method of manufacturing silicon carbide semiconductor device

Assuming that one or more defects satisfying relations of Formula 1 and Formula 2 are first defects, and one or more defects satisfying relations of Formula 3 and Formula 2 are second defects, where an off angle is &#x3b8;&#xb0;, the thickness of a silicon carbide layer in a direction perpendicular to a second main surface is W &#x3bc;m, the width of each of the one or more defects in a direction obtained by projecting a direction parallel to an off direction onto the second main surface is L &#x3bc;m, and the width of each of the one or more defects in a direction perpendicular to the off direction and parallel to the second main surface is Y &#x3bc;m, a value obtained by dividing the number of the second defects by the sum of the number of the first defects and the number of the second defects is greater than 0.5.

It is assumed that a defect satisfying relations of Formula 1 and Formula 2 is a first defect, where an off angle is &#x3b8;. It is assumed that a defect having an elongated shape when viewed in a direction perpendicular to the second main surface, and satisfying relations of Formula 3 and Formula 4 is a second defect. A value obtained by dividing the number of the second defect by the sum of the number of the first defect and the number of the second defect is greater than 0.5.

In forming of a silicon carbide layer, when an X axis indicates a first value representing, in percentage, a value obtained by dividing a flow rate of silane by a flow rate of hydrogen and a Y axis indicates a second value representing a flow rate of ammonia in sccm, the first value and the second value fall within a quadrangular region surrounded by first coordinates, second coordinates, third coordinates, and fourth coordinates in XY plane coordinates. The first coordinates are (0.05, 6.5&#xd7;10). The second coordinates are (0.05, 4.5&#xd7;10). The third coordinates are (0.22, 1.2&#xd7;10). The fourth coordinates are (0.22, 1.3&#xd7;10). After the forming of the silicon carbide layer, an average value of carrier concentration of the silicon carbide layer is more than or equal to 1&#xd7;10cmand less than or equal to 2&#xd7;10cm.

Method for manufacturing silicon carbide epitaxial substrate, method for manufacturing silicon carbide semiconductor device, and apparatus for manufacturing silicon carbide epitaxial substrate

An epitaxial wafer includes a silicon carbide film having a first main surface. A groove portion is formed in the first main surface. The groove portion extends in one direction along the first main surface. Moreover, a width of the groove portion in the one direction is twice or more as large as a width of the groove portion in a direction perpendicular to the one direction. Moreover, a maximum depth of the groove portion from the first main surface is not more than 10 nm.

Epitaxial wafer and method for manufacturing same

A silicon carbide epitaxial substrate has a silicon carbide single-crystal substrate and a silicon carbide layer. An average value of carrier concentration in the silicon carbide layer is not less than 1&#xd7;10cmand not more than 5&#xd7;10 cm. In-plane uniformity of the carrier concentration is not more than 2%. The second main surface has: a grooveextending in one direction along the second main surface, a width of the groove in the one direction being twice or more as large as a width thereof in a direction perpendicular to the one direction, and a maximum depth of the groove from the second main surface being not more than 10 nm; and a carrot defect. A value obtained by dividing a number of the carrot defects by a number of the grooves is not more than 1/500.

Silicon carbide epitaxial substrate having a silicon carbide layer and method of manufacturing silicon carbide semiconductor device

A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. The silicon carbide single crystal substrate has a first main surface. The silicon carbide layer is on the first main surface. The silicon carbide layer includes a second main surface opposite to a surface thereof in contact with the silicon carbide single crystal substrate. The second main surface has a maximum diameter of more than or equal to 100 mm. The second main surface includes an outer peripheral region which is within 3 mm from an outer edge of the second main surface, and a central region surrounded by the outer peripheral region. The central region has a haze of less than or equal to 75 ppm.

The silicon carbide layer has a second main surface. The second main surface has a peripheral region within 5 mm from an outer edge thereof, and a central region surrounded by the peripheral region. The silicon carbide layer has a central surface layer. An average value of a carrier concentration in the central surface layer is not less than 1&#xd7;10cmand not more than 5&#xd7;10cm. Circumferential uniformity of the carrier concentration is not more than 2%, and in-plane uniformity of the carrier concentration is not more than 10%. An average value of a thickness of a portion of the silicon carbide layer sandwiched between the central region and the silicon carbide single-crystal substrate is not less than 5 &#x3bc;m. Circumferential uniformity of the thickness is not more than 1%, and in-plane uniformity of the thickness is not more than 4%.

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Itami, Japan

Hironori Itoh